dnewma04,
I think you'd agree that when it come to sound, only your ears matter. My brother got me into Parts Express. He custom builds everything stereo related. He encouraged a co-worker to buy that DVC 12" for his Mustang convertible. The 15" is a great deal, but requires something like 3x the enclosure volume. I am considering getting 2 of the 15" DVC woofers for my home sub, but have to wait on the money.
The predicesor (sp?) to the SVT was my wife's '91 Z24. I first installed an FM CD changer. Next were all new replacement speakers (got Sony's from Birch Run). Then added a new head unit tape w/ CD controller. That system was the best I've ever heard for such little money using no extra tweeters or woofers. When we picked up the SVT in July, even though my wife drove it to work, I couldn't handle listening to the stock system.
First I added some $14 surface mount tweeters from partsexpress wired in // with factory doors. Some velcro and I've already increased the imaging (since I sit so far back). Then the big event of the ext amp, woofer, HU replacement, and CD changer stolen from the Z24. It took quite some time (8 hours) to fashion a mount for the woofer and amp under the rear deck. I'm very happy with the looks.
Sound needs to be adjusted w/ crossovers, but I bought a house in September. Money is tight and time is tighter. Now it's just too cold to play with that stuff outside. Focus on home system.
Oh, and I find it very funny that Parts Express sells our factory replacement 6x8 speakers for $2 a piece

.
I live in Sterlig Heights, but work in Dearborn. Maybe we can get together some time to check out each other's systems. I'm always open to suggestions.
Aaron