Hello everyone. I am very clueless when it comes to systems and usually have someone install them for me. I'm just wanting to get some basic information before I had to a local mart to get my system installed. I currently have 2 Alpine Type E 12's and an Alpine 450 watt amp. They are both enclosed in a box right now from when I had them installed in my Grand Am. I just got a 2009 GMC Sierra regular extended cab. I would like to put ONE of these 12's and the amp in the truck. I would also like to keep my stock Radio/CD Player if at all possible. My question is, is it possible to have one of the 12's and amp installed in my new truck while being able to keep the stock radio? Will I be running into any complications with this? I plan on putting the 12 either behind the back seat or under the back seats in the cab. Or, would it be better to go on an add an aftermarket head unit? I was trying to get out as cheap as possible at the moment since funds are a little low right now. Last, as far as my XM goes, my trial ends in February. I will be renewing then on the stock head unit. If I were to add an aftermarket, would all I need to do is activate that radio and my service continue? Any information would be appreciated. Thanks!