2005 3500drw 6speed 3. 73rear stock except for AFE stock filter replacement and a AFE torque tube. I'm pulling a 40foot 5th wheel toy hauler loaded wheight is around 17,000 lbs. Need more low end torque to pull the hills better in East Texas and Louisana. Better fuel mileage would be nice,8. 5loaded 15empty. I had a DRPerformance on 2001 power stroke,but my dealer said they had alot of problems with DRPerformance on the 2004. 5 and latter. They were selling edge now the bully dog power pup. Would like to here any info. from people that are using any of these systems,the good and bad.