I've been towing a 41' Weekend warrior with a LB7 Sierra with lots of mods and did great. Could pull grades at 60-65 mph without temps rising and what not. I recently just bought a 2008 LTZ DRW 3500 with 17k miles on it which is completely stock and looking to get a programmer and intake at the very least. I ran a PPE on my 2500 and liked it alot. I haven't pulled my 5th wheel yet with the new truck but noticeable power difference between the two. Any suggestions? I've been told do a PPEI but haven't heard of that, just efi live.