Your question is too general. You need to be more specific. I.e. define the engine layout, application, performance goals. The "benefits" of twin scroll may be positive or negative depending on these factors.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

Thanks hemi

I dig Net and see that all benefits are for engine. We have design/analysis s/w tool for radial machines (meanline analysis).The task is to analyze inflow RT with twin scroll.
As far as I see tweens are used to eliminate cross-influence of cylinder exhaust . I worry that often this scrolls are not symmetric and this may cause different incidence angels on turbine blades.
Really I believe that such effect if it really exists can be neglected and RT meanline calculation can be done as for single scroll.

I can't understand your last post; it seems quite garbled. Are you using a translator?
I recommend you get a textbook on turbocharging. I think the best one in print right now is by Nicolas Baines, but the acknowledged bible, by Janota and Watson is out of print. Good luck finding a copy for less than $500.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz