I sure the stock pump and wiring becomes a restriction real soon from the point that I am at but for me it is not. My wideband sits right where I want it all the way through the 1/4mi, doesnt lean out or lose fuel pressure and the only fine tuning ive done was timing. As long as the LTFT's are at 0 its dead on just with the base % changed for the 60's then the 30% for the E85. I had the exhaust off where the catback adapter goes on the SD's BTW, so about 18" of open 3" pipe off the headers. Just enough to get an accurate read off the WBo2.