dealership, the best buy computer is wrong by the way, you should have 6x9's in the front and the rear i beleive is one size smaller than the 6.5's(maybe 5 1/4), the computer at best buy said 6.5's in back but i ended up cutting the mounts to fit a 6.5
yeah the back are 5 1/4 but I put my 6.5 in my back doors. I bought an adapter for mine that lines up the holes where the 5 1/4 should go so that I could put in the 6.5...But I can't remember where I ordered them from
I checked crutchfield a few weeks back and it said that 5 1/4 fit front and rear. I thought the front were 6x9's but crutchfield said they wont fit. 5 1/4 and 6.5 will fit both front and rear according to their site. I'm sure you will have to cut, like sbsga mentioned if you go with 6.5's. Thats what i plan on getting when i swap mine out.