I installed one on my 2003 2500 with no problem. Works very well. You do need additional rails (adapters) for the front half of the bed. These were included. Recently traded (last week ) the 2003 for a 2006 Mege. Company says it is the same set up. The dealer would not increase the value of the trade for the cover so it was OFF in a flash. Will install after bed liner is sprayed. Had no problems with it and looks good still but I was good about dressing the vinyl. Will paint the rails pre install just to brighten them up.
Good luck on what ever you go with
PS: live in the snow belt, stays out all winter, Have had no real problems with freezing as long as I keep a coating of silicon spray on the tailgate locking strip.