I remember being at the Top G.. Err Clarkson, May, Hammond show @ the dome a couple of years back.. There was a Racechip stand and I remember asking what the chip changes, boost pressure, fuel pressure, MAF, how much overboost, how quickly does it adapt to feedback (Mhz it runs on)? Got a blank stare and not much info. That was all I needed to know...
You want to mod a Turbo BMW? Get a JB... :=):