It was designed to work for street machines as well as highly modified imports. I've had mine for a few thousand miles now and it's working great. I have a 1.8T with the GIAC software. I noticed a definite improvement in the high rpm range when I switched to this valve. See their link for more information.<ul><li><a href="http://www.turboxs.com">Turbo-XS</a></li></ul>