Spoke to the VR God, that is Vince at Stealth, and he's said on an OBD2 car, its not a problem as the Lamda sensor can adjust to it! You may get it squirting a little bit of fuel in too much on full throttle, but not a drastic amount, plus with my mods he recons I may actually get a better throttle response. WOOHOO! Ps. Part Number for a 4 bar regulator from VW : 078133534C at about £55