I think that the best turbo for the ecotec is the GT30.
Boost at very low range is not good for internals and transmission, and a bad flow at higher revs is not efficient. The car was made to have a confortable driving with a good response at all gears, very long ratio gears and a lot of torque since 2000rpm, doesn't have an evo or sti feeling, but it's easy to improve that.
The question is that the new 265hp Audi S3 has a very similar turbo and develops about 310-320hp only with ecu tune, arriving even at 340 with mods. I think the stock audi cams and better intercooler flow and head is the answer. Stock ecotec cams are very bad flowing.
GT30 + cams and the Gxp/Redline will be really sports cars, that's I'm going to do.
Thanks!