its posible that he could have gained a little power, but this would be down to his new redesigned inlet manifold that can flow better and would be bollocks all to do with running 2 dumpvalves

at the end of the day unless you want to do it for looks then i cant see any point imo
anyway if you want it to look impresive, anyone who knows the first thing about turbo cars will look in your engine bay and say, what a t**t he's fitted 2 dumpvalves, i bet thats given him an extra 20,000bhp! lol