That's a cool conversion.
I must admit I thought the late spec BMW 4.8L V8 with sports cat and sidepipes should have been good for close to that anyway ?
Peter does make a fair point re over powered and making the driving less of the entertainment but I guess I am just getting old and lazy 8)
An acquaintance reckoned the trad chassis was OK up to 400bhp (Mind you, he was a Jet Fighter test pilot)