I have a 2001 3500 QC 2WD, I do a lot of pulling mostly between 20000 and 40000 lbs. Right now I have 4" exhaust, Superchips programmer,K&N RE-0880 air filter and Di Pricol EGT, and Boost guages. I would like a little more power, but I dont want to be going through transmission's & rear ends all the time, what would be a good upgrade from what I have now?