I will be piecing together my system as the money becomes available and I need some help deciding on an amp. I am basically illiterate when it comes to car audio, so any help would be awesome. I have pretty much decided on ths sub JBL GTO804 Grand Touring Series 8" 4-ohm subwoofer at Crutchfield.com due to the limited area in my truck. I put in some Polk speakers a month or so ago, also Polk Audio db651 6-1/2" 2-way car speakers — for 6-1/2" and 6-3/4" openings at Crutchfield.com I would like to kill two birds with one stone and get an amp that can power the speakers and the sub(I only have two speakers) but I have no clue what I'm looking for. Somebody let me know what size amp to look for, please.