[Def]

I'd go with a MVS 38 for a turbo like this. Should be plenty fine.

As for porting the stock manifold - it needs it BADLY. I spent about 8-9 hours on my manifold and took off a little over half a pound of material. The tooling clearance bumps are ridiculous, so that's the first place to start. Then work on smoothing things out and gasket matching them. I also put anti-reversion port shapes on the mani (larger than head ports). Basically opened the ports out to the gasket on the mani with a good 20-30 deg taper into the port. That also helps with any mani to head alignment mismatch.