Understand your dilemma . I have the same one.For a thorough installation, not much in terms of cost . I think I am leaning towards the purchase of a spare engine, strip and rebuild , at that point determine the compression ratio based upon how much boost I want to run and then decide how to provide said boost. I guess the SC route has fewer options ( Rushworth performance ) and there is a specialist in Holland that offers a package . If turbo, then loads of alternatives