Here is how to make donning and doffing easier. Listen-up SportRack folks!

Purchase: 
Six M6-1.0 nuts to fit the bolts provided in the kit. Four small velcro 'dots'. Two-sided tape (several inches).

1. Lift box onto vehicle

2. Open hatch and find desired forward/rearward mounting position.

3. Mark on the bottom of the box the forward holes needed to straddle the crossbars at each mounting point. I used masking tape. Tip: Square the box to the rear crossbar. Then mark the forward crossbar. This procedure ensures the box is aligned to the vehicle, instead of the vehicle's side rail. 

4. For each of the four mounting points, slip one of the large plates into position and stick a bolt through the nearest forward hole. Verify the rear holes of the plate clear the crossbars. 

5. Skip this step if the holes fit your crossbars. If not, tape the provided large plates in place where you need them. These will be your drilling templates in step 7. Note: For strength purposes, the new holes should not be too close to any other holes. Adjust as necessary to maximize material between holes. Recommend drilling any new holes for the rear crossbar.

6. Lift the box down. Sawhorses help for the following work. Be careful not to disturb your markings and such.

7. If necessary, drill new holes using the large plates you taped in place in step 5 as templates. Otherwise, skip this step.

8. Assemble the following onto a bolt (do 4 times, once for each of the mounting points): u-shaped bar with the U hugging the bolt head, nut (run almost all the way down), large plate, box (insert bolt from bottom thru the forward hole you marked), small plate, and knob (just a few turns).

9. Assemble the following onto a bolt for each of the passenger's-side (opening-side) mounting points: insert bolt thru large plate from the bottom of the box, thru the box, small plate, and knob (just a few turns). Tip: Apply two-sided tape between the box and each of the large and small plates. This will help you manage the loose stuff when donning/doffing the box.

10. Assemble the following for the driver's-side (hinge-side) mounting points: insert bolt from inside the box thru the small plate, box, and large plate. Apply a nut and tighten securely. No need for tape.

11. For each u-shaped bar, apply velcro to secure the bar to the bottom of the box 90 degrees from the large plate's orientation. This will help you manage the bars when donning/doffing the box.

12. Lift box onto vehicle. Be careful to not scratch your roof and crossbars with the protruding hardware. Luckily, the empty box is light and shouldn't be a problem for two people. Square the box to the crossbars.

13. For each passenger's-side (opening side) mount: unvelcro the u-shaped bar, swing it, and slip the bolt head thru the keyhole. Ensure the bolts are straight. Snug (not tight) the knobs. The u-shaped bar should be roughly level to the box.

14. For each driver's-side (hinge-side) mount: unvelcro the u-shaped bar, swing it, and insert the bolt thru the slot. Apply a knob to the bolt. Tighten this knob and the internal knob until snug (not tight) while keeping the u-shaped bar roughly level to the box. Yes, snugging these internal knobs will be a pain, requiring someone to nearly climb into the box while it is on the vehicle. But, if you mount per these instructions, you should only have to do this awkward maneuver one time. See tips, below.

15. At this point, your box is mounted. Fine- tune the position, and then tighten all eight knobs. Finally, tighten the remaining purchased nuts to the large plates.

16. Finishing touch: I found that the large hinge arms (inside the box that hold up the lid) like to clunk against the box during acceleration and braking. You can hear them. I put furniture for pads on the elbows and the clunking is now barely perceptible.

17. Finishing touch: I worried that water would get into the lock and freeze. I used a business card sized self adhesive magnetic pad to cover go around it (obviously with a hole cut out), and then another pad as the cover. Simply peel off the top pad to access the lock, and stick it back to protect. Stays on at 80mph.

18. Doffing tip: Don't loosen the inside knobs on the driver's-side (hinge-side). Taking off the outside knob will provide enough slack to pivot the u-shaped bars, and you'll never need to climb into the box again.

Now, whenever you doff and don the box, the process is easy:
1. Lift box onto vehicle.
2. Unvelcro and swing u-bars.
3. Passenger-side: Slip bolt thru key hole and tighten.
4. Driver-side: Pass bolt thru slot, start knob, and tighten.
5. Done.

I was worried this might not fit my 2014 subaru forester because instead of mounting on adjustable crossbars, I have the thick (3" x 1.5") fixed OEM crossbars installed (don't even have side rails); but to my relief, it fits perfectly! I'm currently testing out the carrier locally before a cross-country trip. I'm really surprised at how little the felt drag and wind noise is; it's barely noticeable. I've also driven in the rain for two days and the inside is perfectly dry. It's 16 cubic feet, which is definitely on the large side and exactly what I wanted (see pics). I would mention that this carrier comes with brackets, not u-bolts. At first I thought it was a pain because it takes a bit more time to install, but actually the brackets provide even more customization to the size of the crossbars (good if I want to use on another car with thinner bars). Once I complete my journey I'll update my review, but so far I'm really happy with this purchase!

Update:
I completed my 2,000 mile trip last month and it worked perfectly; nothing negative to say whatsoever. As soon as I fully packed it, the little bit of shaking I previously encountered went away. I think all carriers are like this. It's not that they don't fit well or are too loose, but without contents inside the top will move a little given that the bottom is tightly anchored to the car and the top lid can shift a little. But honestly, even when it is empty, I only notice that when I hit a bump or something. The unit is more than sturdy enough to handle everything I stuffed inside. That being said, go by the weight limit that comes with the paperwork. I had about 120-150 lbs loaded up (distributed evenly) and had no problems.

Traveling from Phoenix to Baltimore by way of Seattle, I managed to carry all my worldly possessions in a compact (though deceptively spacious) Honda Fit thanks to this device. It arrived at my apartment in a ridiculously long box. Mounting was a snap"”I used the Rola Roof Rack, which is wide and flat, and it mounted fine (though it was a tight fit). This cargo box was just shy of being too long for my subcompact: it bent the rear antenna back a little, and and overhung the front windshield just a tad. I actually liked the fact that it went so far forward, because it wasn't so far that it obstructed my field of vision at all, but the fact that I could see it if I craned my neck gave me reassurance that it was still hanging in there.

The actual interior space on this box is a little strange: the usable space is rather narrow and not particularly high, though again, it is quite long. I imagine it would be great for skis or surfboards, though I was using it for more general cargo so I had to make some adjustments to my planned packing schema. The bottom is not flat like you might expect, so flat-bottomed items are not particularly efficent to be placed inside. I kept most boxes in the car itself, and used this box for two guitars (in soft cases), a number of blankets and pillows, some parts to a lamp and a desk, and a few small shoeboxes, among other things. So it is indeed quite roomy if you are able to adjust to the irregular shape. Again things like blankets and pillows are a great use of its interior.

I rode through all manner of climates with this box, beginning in the sweltering Phoenix summer (and I drove around Phoenix for some weeks with this box attached), through the windy mountains of Coastal Highway in California, rainy Washington and Oregon, and snow in the mountains around Mount Rushmore. At several points the weather was so atrocious that I worried the entire box might be flooded. I did not open this box until I arrived at my final destination, and when I did so everything inside was perfectly intact. There was no indication that any water had leaked into the box.

One of the main reasons I purchased this box was that its slim profile seemed like it would be quite aerodynamic, and indeed it was. My Fit averages about 40 MPG on long highway trips, and on this trip it hovered around 37 MPG, which may have had more to do with the increased weight I was carrying than this box. Granted my car is relatively low-profile, so a higher SUV might notice more of a drop off, but on my Fit I don't think it was responsible for more than a 1"“2 MPG loss, which I found quite impressive. There was also very little wind noise. You could tell it was there, but it was a minor background sound, you really had to be listening for it to detect it. More noticeable was the sheer wind effect, pushing my car slightly to the side on particularly strong gusts of wind, but this was only apparent during the worst weather conditions.

An added bonus of the sleek aerodynamic effect: this box looks cool. I really liked the visual effect it had on my car; it seemed to complement the slick look of the Fit.

In short, I would highly recommend this cargo box rather than paying more for a fancier name-brand box like Thule, because I just can't see what Thule could offer that this box doesn't already have. It held up to everything Mother Nature could throw at it, and looked great doing it.

I actually really enjoyed using this product on my ski trip traveling 800+ altogether. I do like the price of this item, as others cost way too much money (I just wanted a rood storage option). Here are some notes:

- Packaging came absolutely destroyed and is the only reason I didn't give 5 stars. I normally don't rate based on shipping, but this box was so ripped up, 1. I am surprised the actual item wasn't damaged, and 2. I think this company needs to talk with their shipping partners.
- Install: Read the other comments about install, they explain it perfectly. It can be done easily with one person, just give yourself at least 30-60mins to find the perfect fit. After that (and assuming you keep your crossbars the same width), the item will install in less that 5 mins in the future.
- Use: Didn't have any issues with it making too much noise or moving around. It is a tight fit, and I even rode with it empty for a few days to ensure it was working. Easy to access, key/lock worked nicely. Had no issues. Only bad thing I can say is 1. The instructions don't help you very much, thank you to the other customers who gave more detail/feedback 2. the bottom holes are covered up with stickers they give you, would be nice to add some sort of tube filling material to create an air/water tight seal. The box fit just about perfectly as far as length on my 2012 Forester, I could have moved it further up if need be, but would rather set it more towards the middle/back. The hatch opened 98% of the way there, so I was fine with resting the little bit left on the box from time to time.
- Size: The sizing is on the smaller end as far as width. This is nice if you want to mount something else on the other half of your roof rack system (possibly another ski/snowboard mounting system, kayak mount in the summer, bike mount, etc.). I was only able to fit two boards with bags included. If you want to fit more skis or boards, you will need to take them out of their bags, possibly remove bindings for 3+.

Overall, like I said, a cheap and reliable solution for roof storage. If you have 3+ boards, you may want to consider a wider cargo box.

Great product. It's light weight, watertight, flexible when open but sturdy when closed. It has three latches holding the front, middle and rear shut and you cannot lock it shut / remove the key till all three latches are completely closed. Straps from bags have a tendency to interfere when closing and this safety mechanism will ensure that it is completely latched b/f you can remove the key. Assemble the mounting brackets b/f you lift it onto the vehicle and it'll go smoothly. I've had this completely stuffed w/ luggage and no problem. This winter I'll see if I can put three snowboards in it which is the real reason for my purchase. About 1/2 MPG is lost b/c of additional wind resistance. It stays stable and does not wobble around up there on my minivan. Again, great product, great price. No worries with it.
I purchased from an Amazon vender which was risky if a return was needed b/c postage would be on me. It arrived UPS in perfect condition. It'll come in a big long box that weighs very little.

Just completed the Co ski trip and I put 3 boards w/ two pair of boots, a pair of ski's / poles / ski boots along with 3 frozen pizzas up there in this thing. The bindings on the boards are the limiting factor but maybe 4 could be included - but I know three fit. Also, we traveled through a storm. In between bad weather I was driving 80 mph into a 40 mph wind and this carrier barely wobbled ( I was watching the front through the sun roof ). Extremely impressed with this thing. It held up through some extreme windy conditions. It's a great buy.