Door Speaker Upgrade

[don corleone]

Yesterday i upgraded the Front door speakers with JBL Grand TOuring 427's. http://www.crutchfield.com/g_51200/4-Speakers.html?tp=102 the speakers do not fit flush in the housing because of a bracket that the pioneers had. They also do not sound nearly as good as the pioneers. This is my problem. I think it may be due to the fact that i am not using the tweeter so all the sound comes from a lower area, but the bass doesn't hit as hard and the sound is lower. I was looking at crutchfield.com at some sealing caulk to seal the speakers better i think this might work. but keeping with the stock component setup that works so well i was thinking about getting the Infinity Kappa 42.9i 4" speakers for the front since they have a standalone tweeter that can be mounted in the stock position and moving the JBL's to the back doors. this would keep the system stock but new. is the problem that there should be components in the front to maximize the sound quality or is it the seal on the box.

I was also thinking about getting the Infinity Kappas for the back and cutting the back door to mount the tweeter so i would have full components front and back like the newer Lexus'. Has anyone ever tried this and is the sound quality a huge difference.

Thanks for any help/advise