ford power u are correct in that sense. all of my experience in tuning cars (including my own xc) with haltech and ems etc didnt include the use of a hego sensor in the exhaust permanently. I kinda forgot about that sensor reading what would be exiting the manifold. the computer would continuously trying to alter the mixtures, one minute it is spot on, then a gearchange or lift off the accel, and its all over the place, and next minute is it spot on. back to the books for me. lets get 1 thing straight. if ondole wants to run his bov to the atmo, or another aftermarket bov, let him do it. its all about being individual and stepping outside the square. if nobody thought differently, we would have a very boring world!!!! look at street tuner for example. being different, being adventurous, and bam! 300kw!