[A4] new stereo install

[JeffR]

well i just made the switch from a 93 prelude to a 2000 1.8t a4. so far 
i am loving every second i can get driving it. a couple things though. i 
am trying to put a new stereo in it. and of course im having troubles 
finding mounting kits for a new head unit...just curious on the 
different solutions people have used.  i dont have the bose system and 
the sound quality is just not up to par. im also wanting to put in some 
mb quart components and it looks like the front is 5 1/4" and the rear 6 
1/2" is that correct? crutchfield doesn't say anything about the front 
speaker sizes. any input would be much appreciated.

jeff