I am pushing 13+lbs of boost and I am still on the stock fuel pump. it is all in the tune. I havent had the chance to dyno with the higher boost but I am over 400hp with 10lbs of boost. Just search ebay for a +2lb lightning pulley they are on there from time to time for less than $100. Your stock Roush tune can compinsate for the +2lbs but unless you are running an aftermarket tune you will hit the speed limiter pretty quick.