Very interested in this as I'm looking for ST170's to base a turbo project on. Main sticking points I've come across are intercooler installation and - as you do - I'd ideally want to keep the VVT as my feeling is that it could be used to get better low down/off boost performance. Spoken to a couple of places known for Zetec Turbo conversions and they've suggested ditching the head for a standard black top, but don't really want to do that. Seems a shame to loose a good feature of the engine.

Cheers.