Depends on the turbo. Most don't benefit from much of anything on the actual outlet part that is post-turbine wheel beyond smoothing the casting and maybe rounding sharp edges if there are any. A lot of companies port the living hell out of that area because it's extremely visible to the purchaser and it looks like major work was done. Well... maybe a lot of work was actually done, but it was 100% completely and totally non-functional.
The guy who ports our turbos knows what he's doing and he is truly one of the best in the world. He's been doing this specifically for around 36 years and he's very, very good. He will ONLY do work that is FUNCTIONAL and BENEFICIAL. He really couldn't care less if it looks massively ported and super impressive when it comes out of the box. He stops when there's no more benefit to be had from the work and he absolutely will not port to the point where it reduces efficiency (as is somewhat common) or threatens the integrity of the housings.
We've actually done a lot of turbos that were already "ported and polished" from a handful of other companies. With only an extremely rare exception, they're nice and shiny only as far as you can see into the housing. Stick your finger up in there and it's totally untouched and rough as soon as its out of site. That's not what you get from us. The housings are COMPLETELY ported all the way inside, even where you can't say and most shops cannot even reach....