dvd, iphone, subs?

Hello, first car information. 03 Chevy Monte Carlo, has stock headunit with onstar, factory amped non-Bose. I do NOT want to keep onstar. The goal is to have video for sure in the rear. I want subs, but not have to thing. I think I like the pioneer avh-p3200bt? But what is the release date? This is like the max I want to spend on a headunit. But with this one I only have to buy one plug for my iPhone 3gs. Is there any other headunit comparable? Rear screens? Cheap? Pyle? Subs?/Amp? I like kicker?, Memphis?, mtx?, pioneer? I would like to keep the same brand sub amp combo, yeah I'm weird like that. I like loud, but not crappy loud. Also should I just relocate stock head unit? It does have oillife monitors tire monitors and such. I already have a viper alarm installed when I bought it new. I need three layouts cheap, cheaper, better than stock. Thanks in advance for your help.

Any sugestions are helpful

ok forget the avh-p3200bt. In order to do this with subs, gonna have to sacrifice front dvd, opt for rear dvd only. I will use this headunit MVH-P8200BT Why, because its new and bluetooth, and fairly sure will work with iphone 3gs? Now I have $300 left to use on dvd/screens, subs, amp. I want hard hitting, obviously can't do much with this budget but some options please? I don't care about main stream brands just want decent stuff.