Yeah I know what you mean. Twin scroll is a better turbo, but is it better than having two normal turbos?

Well, based on the 'official figures', the single twin-scroll has the same power and same torque, but the torque is usable over a wider range.
Having said that, it's well known that the previous twin-turbo 135i motor was underrated by the 'official figures'.

But in other news, BMW are bring back the 'is' models. I can't remember whether it'll be a 135is or 335is or both, but apparently they'll have even more power and torque (not sure if there is a mechnical difference or just an ECU different though).