So did you find a compressor map for the turbo (which I doubt exists) and work out all that jazz that I have hardly any understanding of? Or was it more of a case of "that one looks f-cking huge and cool, I'll bodge it on". What turbo can get an SR to 400bhp on standard internals then and make chronic cho cho noises and spool by 3,500? For that matter, what about an M50 (more just out of curiosity). Edit: No troll.