Remove the battery and it reverts to stock. I've just spent 6 days driving standard and mpg is exactly the same but it is a totally different car. I've been considering selling it but went back to votex to set it back to 6,6,9 and I cannot believe how fast and how sharp it is. The throttle response and instand power has blown me away all over again. What a car!!! All you guys running stock, you are seriously missing out on what an amazing car the gti can be!!!