I replaced factory tweeters in a Nissan Frontier with after marker head unit. I just wired directly to factory tweeter plugs, no external amp. Highs are much much better now.

Changed my front door speakers and added these. No amp, just plain stock stereo and sounds pretty good. I used a double spade connector on my new front door speakers and these tweeters are just connected to them, new 6x8 Rockford F's punch. This location in the pic turned out well. The wire is tight behind the plastic then just used strong double sided tape. No amp needed.

Added to a 2010 F-150 factory set-up that pushed WAY too much bass. Couldn't be happier! I cut holes with a 1½" hole saw and finished with a steel file to make the holes large enough to fit the tweeters. If you're handy, these speakers are a breeze to install. I chose to mount them in the door, just forward of the side glass defroster vent. Added a nice amount of treble and brings the sound up off the floor. I highly recommend these tweeters. I may buy another pair to mount in the rear of the half cab.

Installed under the front door speaker panels on a 2004 F150, door panel removal not required. Remove the speaker grill, upper armrest and existing plastic plugs. Had to route the speaker hole out another 1/4 inch in diameter with a dremel tool. Used the flush mount with the tweeter removed as a template. The speakers fit flush using the flush mount metal retaining ring included, install the ring when routing the wire down. There is a hole to route the new wires down, look through the armrest above the factory speaker. I soldered the wires to the existing solder joints on the factory door speakers (positive is located on the lock clip side of the connector, just trace the wire to the solder joint) did not cut the harness. Speakers greatly enhanced the treble after adding a slim line subwoofer behind the back seat and adding a 56 watt RMS per channel head unit.. These speakers are low wattage, so an additional amp is not required.

Worked in my 2008 Jeep Wrangler Unlimited. Just used a razor knife to round out the stock tweeter housing and put these in. Now they look stock but sound so much better. Highly recommend for a Jeep upgrade.