Quote Originally Posted by I800C0LLECT View Post
The toughest part is getting your doors done right to keep the vibration transfer down. I'm going to add some foam to get some separation. You also want a higher Qt, ~.55 or higher, in your mids if you decide to use them in stock locations. My speakers are border line so the mid-bass can't take a lot of power but I time alignement, attenuation, and my rear 6x9's to help. Mids and rears are crossed with 18db slope @80hz. It sounds GREAT when crossed with 24db slope @63hz but that's when I pick up a lot of vibration in the door card.
I assume you've tried Dynamax (or a similar product) to help with vibration? This always seems to be one of the problem areas when upgrading sound systems. Thanks for the note on the Qt, a good piece of information to know. Though I would be a bit concerned of them getting bright (as you mentioned).

Quote Originally Posted by I800C0LLECT View Post
Unfortunately, that's where my XM module was located on a bracket and the area didn't look condusive for the size magnets on my subs.
Seeing that mine is set up for XM as well, I am wondering if my module is in the same location which would preclude a dual sub setup.

Quote Originally Posted by I800C0LLECT View Post
Everybody thinks my mids are creating all the bass. The bass is in front of my windshield. It has a few odd cues because of the dash layout but I'm very happy with the results.
Given the physical dynamics of the car, it does seem that there are some weird reflections going on. Have you found ways of accounting for this, aside of crossover points (type of tweeter, speaker direction)?

Quote Originally Posted by I800C0LLECT View Post
Existing speakers for stock 04 grand prix are 6.75" mids and a 3/4" tweeter. These are components with basic filters on the stock wiring. However, not all 6.75" mids work. I had some Pioneer 720prs mids I wanted to use but didn't feel like fiddilng with the factory speaker pod/mount.
Mine is an '06, but I assume it is the same? If I chose to go with a component set, I assume I could bore out the hole a bit more to fit a 1" tweeter?