I'm definitely wondering whether he guess-timated the 410hp from the sum of each product's claimed power or did he actually put it on an dyno.
EDIT: Have a look at this article SCC Evo Orgy The Evo is a beautiful car that responds well to upgrades, but from his list of mods, I don't believe that 410hp (or about 365whp) would be the result. Maybe he didn't include the complete mod list, or he's rounding up his numbers... a fair bit.
i know a kid that had one of those that tried to increase his boost to some ridiculous hi level and ruined the car. I think he tried to like almost double the boost and didnt change anything else and the car would barely run when he traded it in!