So I am trying to plan out the system in my car and I am getting more or less stuck in my ideas so I figure its time to get opinions and advice.

My00

Head unit: pioneer deh-80prs.....pretty set on this.

Amp: Alpine pdx-4.....i want to keep everything out of the trunk

Door: Already have lanzar max 6.5 components. I needed something to replace my failing pioneer coaxials and these were cheap. Surprisingly with the current crap sony headunit they sound great so i want to at least give then a chance with a good hu and amp. Easy enough to change later.

Rear panels: here is where i have trouble deciding. I want to have great sq and volume. I know without a sub its gonna be hard to get really good reproduction. Anyway so i have been thinking in several directions. Easiest choice would be something like infinity ref 5.25. Fit good and sound good. Polk 6501 6.5 shallow mount components. Not sure if the size up will be any better at producing quality sound at volume as a good set of 5.25 components. I dont think any non shallow mount 6.5s will fit. If I thought i could get 6.5 subs in there i might try that. The other direction would be 5x7s but again i dont know that these will better than a good 5.25 comp set. Any ideas on this? Whats the biggest magnet and basket i can squeeze back there if i pound the metal?