If you only get 310 from that, it's a laughing stock.
Think about this... There is a company that can push 200hp out of a Zetec SAFELY local to me.... THen you drop a turbo on it to knock at least 300 if not Terry's kit to hit 325hp.
So therefore the twin turbo Duratec should hit higher... I mean stop me if im wrong, but It should be higher than 310... maybe thats just super down-tuned?