Also, i think the best way to go about choosing a new turbo, would be to have a power figure in mind, boost level u want to run, and then u can work out ur flow and then by looking at turbo maps (compressor & turbine) u can correctly choose the best turbo for ur application
Actually, bugger it, ill make a phone call and get some definate info, as i need to figure out what turbos i can run.