I was new at this game once and I know how you feel. I hope my two cents will help you... I purchased a Alpine CDA-7893 for $350, and later found out you can get them for under $300 on ebay.com I should have waited but I didn't. Well I think that headunit is awesome. I say go for that Alpine CDA-7893... You'll thank me later, it'll be worth time and money... Hope this helps you!
~My Sound System~
HU: Alpine CDA-7894
AMP: MTX Thunder81000d
KnuKonceptz 0ga Amp Power Wires/Kit & Tsunami 4ga Power Wire
SUB: (2) Blown 12" MTX Thunder8000 (Awaiting Arrival)
Cap: PPI 1 Farad