I just got my new Infinity Kappa's installed, as well as dyna matting some of the plastic joint squeak spots. It sounds much better compared to stock, but those doors are so flimsy. The Kappa's are 6.5's and are powered by my Sony CDX-MP70 deck. The stock speakers looked to be of pretty high quality, but the new Kappa tweeters are leaps and bounds crisper. The mids are much tighter now as well.