It's not really a power adder, its a supporting mod. If your running a 400 HP tune it is'nt really needed and probably wont help at that level. If your running mid 400s- 500 HP the stock fuel system cant keep up at that point and a lift pump is a must to get the full potential out of the tune. I have my lift pump set up with a toggle switch and only turn it on when I'm going to do a good long hard run, like at the track. If I'm just passing someone on the highway even though I get into it pretty hard sometimes I rarely turn it on even if I'm on my race tune.