Hi guys/gals. I have a '04 GMC Sierra CCSB 4x4 Lb7 Allison 5 sp. I do alot of pulling, heavy equipment, construction supplies, 12-15k lbs. with my equipment trailer. On the big island we are either going up or down hills, 8-20% grades. I've got a Banks Big Head wastegate and aftercooler, Edge...