Wotcha and welcome - that is indeed a tidy looking motor, sounds like you have sensible mods there already and with the STI spec you have brakes suspension roll bars all beefed up as well - with 330bhp I'd say just keep adding shell Vpower & sticky rubber.
I would encourage you to get a forum sticker on your vehicle but we seem to have some supply issues at the moment but hopefully that is being rectified :D
ah just thought have your cam belts been done - if not it would be worth looking at those and possibly changing the coolant pump for a design that doesn't cavitate at high revs, possibly a higher pressure oil pump as well - not essential but for me it would be peace of mind