help install aftermarket

im putting a system in my truck and was wanting to know if it was a good choice of componets with a budget of about $550. Here's what i'm looking at: head unit:Pioneer DEHX7500S amp:Crunch P1-1650.4n 200wx4channels 4ohm door speakers: Four Kicker 40CS684 6"x8" 225w max, RMS: 75w 4ohm subs...

Well, i just purchased a 2008 Chevy Impala LT with OnStar about 2 months ago and now im looking to install an aftermarket stereo and amplifier. The thing is, i dont want to buy the expensive *** harness LAN kit that retains all the OnStar settings and chimes. The crap costs 140 bucks on ebay...