I have done the fans and the underdrive pullys on my previous truck and do not recomend them. I had the chip, headers, exhaust, k&N and throtle body riser and the thing ran like a dream. when I added the pullys it did weird things to the charging system and the electric fans do not cool near as well as the reg one. In the mid summer you will have overheating problems while in traffic. I had the highest capacity fan I could get and still had to take it off and put the reg fan back on it. Get your horse power from somewhere else and keep the fan and stock pully system. Or at least only change your crank pully. If you change the water pump pully it will also cause temp issues. On cars with smaller engines and loads you can get away with the mods but in trucks they dont seem to take. In my expy I have the borla exhaust system(except headers) and the k&n filter and it made a difference right off the bat of around 15% fuel economy and noticable power increase.