What was the age difference from your 2500HD to the New 3500HD? If they were both diesels and there was more than a couple years difference in trucks, then the new truck would have had a TON more power than your old one. On top of that, if you were using it to tow a trailer, the new 3500HD's have a sway control system built in, that alone would make it tow better. Sounds like a case of "Buyer's Remorse"... You just need to understand, "once you put tags on it, register it and drive it off the lot it is considered a used vehicle - they will not give you your money back.