cossierich ran one at 453 hp on a stock port head with just a bd14 inlet cam at iirc 30 psi.


I would think you should be ok at 20 psi, I ran a t4 on a stock port head with bd14 inlet and could run 22 psi before surge was an issue.


ask stu or tony if he could write a chip for just 20 psi across the board, that's what I would do they are so much more responsive roller bearing turbos and a gt30 with the adaptor rear housing will be a simple bolt on affair


tbh if I was you id want it live mapped anyway to get the best out of it, any off the shelf will be a compromise it has to be on the safe side imo.