Hmm I did some thinking and seen lots of guys online regret not going XL from the get go plus I think I'd rather have some more top end as well. I think XL is the move
I think it's a matter of horses for courses really. Comes down to what you're doing with the car. The power gain is in the realm of 20-30whp, and also depends on fuel type. But the Standard still works incredibly well, comes into boost a little sooner, etc.
I think for any sort of road or track racing outside of the drag strip the Standard is the way to go.
Sorry if I was unclear, they do use the same turbine wheel. It's just a matter of we go through XL's in a 2:1 ratio almost so the last batch we had consumed the stock of wheels we had available and the Standards move a little slower so we still have them available.
They are the same wheels in both turbos and the difference is the housing.