I'd stay with the GM-8/Turbomaster for the mech conversion, at least for a while, to allow sorting out any nitpicks and give you some experience with how the engine/drivetrain perform. Once you've settled in, then consider some additional changes.

The Holset HX35W uses a boost pressure actuated wastegate. These normally produce, in stock form, a max of about 15-psi. With an intercooler, this would be OK on a stock compression ratio engine and close to stock 4911 fuel rates.

Jim