Building a system; hit a brick wall regarding a new head unit. Advice/help!

Hi everyone, I'm new to this forum. Being my first post and all, I'd like to start off with a few technical questions!

I'm building a system; I haven't built one in a long time. A friend of mine who is incredibly knowledgeable in the subject is helping me along, but we're both getting bogged down in the head unit department. I've decided I want a single din over a double din. I've also ran into a brick wall regarding my front door speakers. They measure 6 3/4". Are there any over sized 6 1/2's that would work? Are there reliable 6 3/4" speakers? Any advice would be really awesome guys, thanks! . Help!

I have a 400.00 budget for a head unit. Any advice would be really awesome guys, thanks! . Help!


Regarding the rest of my build here's my potential set up:


Car: 1996 Acura TL

Heavy duty Optima Battery, will eventually get a heavier duty alternator after everything is assembled, tuned perfectly, and know the limits of the system. I don't have to have it maxed out all the time; I want to be able to hear things when I'm in my 60's.

Front/Rear: 6x9 three-way Infinity Kappa 693.9i

Tweeter: infinity Kappa 10.9t

Interior Amp: Hifonics ZXi150.4 1200W RMS

Sub Amp: 3000W RMS Hifonics HFi3000D

I'm wrestling with two different kinds of subs. I've had subs Alpine Type R12's powered and they sounded fantastic. I've also experienced the raw power of duel JL Audio 12" W7's.

I'm thinking getting either a single 12" Alpine SWX-1243D 3000W RMS or a single 12" Alpine SWR-1243D.