Can i put low comp pistons in a stage 3 2wd cosworth ??

Im running 4 x Greens, 500 intercooler, Breather system, stage 3 Ahmed chip, 4x4 head which is ported and polished, 200 block which is wire rung etc etc

I want around 350 bhp but in future will try to go more.

What would be the best cam and piston combo?

If so which ratio is best? (its all a bit confusing for me)

My engine is out ready for the pistons and cams now so i would appreciate your help

Thanks