GTi6 Turbo

[Ruan]

I also heard the XSI head flows better, larger ports. They Im guessing smaller ports on the GTi for higher gas velocitys

I think that's another rumor like the 1.8 head flows better than a gti6... It's one of things that comparatively, yes, you can probably get more out of a 1.8 head if you literally spend about £10k on rediculous port shaping to eek every last bit of performance out of it because there's shitloads of meat, but you could have saved yourself £9850 and just gotten a GTi6 head that'll flow 95% as well...