Yup it sounds as if there dead to me, oh well, don't worry about it, you'll forget the 6x9's soon especially if you have a sub in the back, even an average 10inch is a huge improvement for bass characteristics when compared to that of a pair of 6x9's.
As for you rear speakers, I suggest you just throw in a pair of 6inch coaxials in the back, and start concentrating on your front stage. As nice as an 8inch woofer up the front would sound without a decent tweeter, midrange combo you'd be loosing a whole heap in the audio spectrum, basically your whole car will be producing sub bass freq extrememly well, but when it comes to the higher levels, they'll be a large gap.
If you have the patience and finance sufficient for a good 3 way setup then, yes I suggest going with the 8inch up the front, then add a 4inch, of 5inch, midrange, and a tweeter, but if you don't, a properly installed 6inch split system will do wonders for your car.
A single 12inch, or 10inch, with a good 6inch split system up the front is a tried and tested solution for quality car audio, you won't be dissapointed.
Hopefully that helped.

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Source Unit: Clarion DXZ925Front Stage: Pioneer TSW1635 Bass Bullets Sub Bass: 2 x JL12W3D2's Front Stage Amp: KACPS401T Sub Bass Amp: JL500.1[Edited 1 time by Galactic Soap on 07 October 2002 at 20:06]