I assume this is a GT model? ST180 or more probably a ST200?
If this is so, it's a wast of time and money trying to turbo it! (sorry! IMHO!)
Buy a GT4 instead! I had one! it's completely different to a GT! 4 wheel drive, 205+ BHP and if you get the right model it's just like a World Rally Car!
See http://www.gt4oc.net/
Col, August 2007