I vote 3500 SRW, If they are not going to be towing in the 25-30K GCW class, then the 3:42 rear diff won't be too bad, also just a little more GVWR than a 2500. Cheaper on tires, washable in car washes, and as mentioned more capacity. The Aisin is the best auto transmission available in a light duty pickup, yes the 3500 SRW and DRW are concidered light duty trucks. However if they can get away with a gasser 2500, they are cheaper to maintain and have less restrictive smog crap, that can run into some big bucks after warranty. If I were to buy another truck, I'd sell my heavy 5ver and get a Hemi 2500 or a Nissan Titan with the Cummins Aisin combo pickup.