What is the best Spec to go for using a GT30 on a relatively standard engine, 205 block?

I love the power delivery of my 803's/0.48 set up at present but want more power.

Am I right in thinking that fitting lower comp 4x4 pistons and a bit of head work with some bigger injectors will do the trick? what sort of power can I expect on this setup and can you recommend doing anything else at the same time double valve springs etc etc


Cheers