My BD Heavy Duty Valve Body was one of the first upgrades I bought. I installed it myself ( about 2 hours in the driveway ). And it really changed how the truck feels. When the truck was new, it just felt like the shifts were soft and weak. Especially the shift into overdrive. Now the shifts are very solid. I am told the more solid shift and the increased line pressure actually extend the life of the transmission. Less slippage means less wear on clutch surfaces. Anyway my Heavy Duty Valve Body has been in for well over 100,000 miles now. And I'm lovin it!