[asperformance]

for the 2003MY the JDM STi cars installed a twin scroll turbo system and because of the shape of the exhaust manifold they redesigned the sump from the very square shape used on everything else to a much shallower shape at the top with one long "leg" - this style was then slightly rationalised for the 2006MY and used on all EJ Turbo cars including the 2.5 STi's.........

as a std sump this is better than the original BUT its wrong to say that a proper baffled sump won't add anything as it further improves the factory set-up

whether you justify the set-up would depend on your exact use, power targets and budget