That's a good plan. For the pre-amp signal, I would suggest to tap it straight from the tuner like Ken did for this car, absolutely clean signal to feed your amp

http://www.xoutpost.com/bsws-mobile-e...t=Ken+dynaudio

I have a similar set up, except I have Dynaudio MKII in the back and Dynaudio 340 in the front with an extra pair of Dynaudio 100 on the dash board. All these are powered by the McIntosh MCC406M. I also have a JL Audio 12W6V2, powering by the JL 500/1 amp. Make sure your crossover frequency for your dashboard tweeter is around 2500Hz, it makes the sound image much nicer and more lively.

If you don't mind carefully modifying the OEM speaker bracket a little bit with some grinding, you can fit the 6.5' woofer in there instead of 5 1/4 in. It's a lot of hard-work but it's worth it. You can contact Ken at www.avincar.com. He helped me alot in the project and he is a super nice guy . Hope this helps.