What's the URL for the site? I'd be surprised if you could get a genuine verified 400|PLS| bhp out of any Evo. It harks back to the Scooby 22B story, at first it was claimed it had 350bhp |PLS| then when tested it wasn't any more powerful than the Sti's.
The owner does lurk (his words!) on this board, but I think he prefers to to keep a low profile, which is fair enough. Although he didn't get the best BHP figure, look at the torque, 370lb/ft http://www.ltregister.f9.co.uk/graphics/biggrin1.gif border|EQU| 0 align|EQU| absmiddle >. At the Brighton Speed Trials, I believe he posted a 12.67 second quarter mile time, which is pretty impressive. I think he was going to get the car fine tuned by Co-ordsport, so Richard, if you're reading this, I'd be interested to know how you got on.
I have lurked for 18 months and finally have to comment!
The RS450 was never 450bhp, just a model name although Ralliart UK's target was 450ft/lb torque. Looking at the power graphs from Tuning Japanese check out the difference in torque - the biggest horsepower was 357bhp but only 282ft/lb torque compared to 369ft/lb from the RS450.
As we all know, torque is the bit that really counts in every day use - I've got one so I can vouch for its effectiveness and yes I'll put it on some rollers soon!