I would like some advice,Im looking at 2 used 3500 daully 6.7 with the 68rfe. One is an 07.5 and the other is an 08 both bighorns. The 07 has 16k asking 39k and the 08 has 18k asking 35k both are on the west coast. I know the 6.7 and 68rfe come out in 07.5 was there any issues with the 6.7 or 68rfe in the early stages of production. I plan on towing a 5th wheel that's about 15k. Anything I should stay away from or watch for, Any advice would be much appreciated. Here are the last 8 of the vin's if anyone is able to check and see if any issues were reported. The 08 is 8G1403362, 07 is 7G823186.