Imo your in danger of puting the cart before the horse

Your turbo should be matched to the spec of your (new)engine.

My advice would be to sit down either with your selected tuner/engine builder and work out what your spec is ultimatly going to be and take things from there. No point in spending a lot of money now to find out that the turbo unit you have invested in is not best suited to your car after engine work.