Originally Posted by
mentalasanything
My old RST ran standard boost, fmic, exhaust and filter and she made 144BHP atw. I take BHP figures that people throw around with a pinch of salt unless there's proof (proof which I have for both of my claims!)
Lee

The op is aiming for 250 bhp and a standard engine and mfi system won't do those numbers,not on an accurate rolling road anyway.
Tuning a cvh turbo is a very well trodden and documented path and if it was as easy and cheap as bolting a turbo,exhaust,filter,fmic and chip to 1 then every cvh would be a 200 bhp + monster as nearly every rs turbo has that spec nowadays.