6 1'2", 6 3/4", and the rare oversized 6 1/2" all fit in the front doors. I think that some older style Infinity Kappas (not as old as the green cones, the first generation silver cone 3 way models)came as 6 1/2" but with a collar to fit 6 3/4" openings. The tweeters are not that complicated. If you do replace them you can bypass the fatory cap if you have seperates and a crossover or keep it if you are just replacing the tweet and running it off of the factory deck. I kept the cap and put in Infinity Kappa tweeters and Infinity Kappa 6 3/4 two ways in the doors.