oil
1st remember, i was giving seat of the pants, not dyno info. what i know is that i still could hit 125mph and the end of both straights at vir. as far as sucking oil-notice that the crankcase hose goes way down on the aem and then sucks the oil through your maf-on the steeda its filter,maf, then breather. so oil ends up where it should and does not suck through the maf. as far as we can tell,you need that vacuum for car to run right. with breather you are losing that vacuum and building up a ton of pressure in the crankcase. after installing my breather on the aem last year, i noticed oil seepage from the valve cover on track days-no more.