With some trimming a little time, I have a pair of Infity Kappa 6 3/4" in the rear deck and 5 3/4" in the front. The front grilles are trimmed easily (making room for the tweeters) but I found that my rear deck needed to be re-built so I up-graded the speaker size as well and dynomatted the metal also.They are powered by a Pioneer 3700 deck that I am very happy with, that went in easily. I suggest upgrading any wires that are used in the installation. I find that it is easier to do the job once while things are apart rather then ripping in to it again later. I also found that it was eaier to exclude the factoy fader by installing my own wires and bypassing any previous applications. I also used styrofoam baffles to insulate my speakers which make a world of difference. They are inexpensive and effective in protecting both sound quality and the speaker itself.