The "cast of characters" has been pretty well laid out; notation of engine wear, turbo wear, PCV system wear, valve seal wear and OK's given to use of a thicker oil.

The funny thing is that nobody ever has a suggestion on BRAND of oil when the "mysterious consumption" question comes up. All I can add there is that cheap oils, though proper, seem to vanish faster than good ones.
As they say, "A quart per 1,000 miles or less is OK". Heaven knows, that's of little comfort.

As purely anecdotally based suggestions I have good memories of Castrol 0W-30 and Mobil1 0W-40; both being the European Formula. My turbo experience was with Saabs and I didn't take notes.
However, every engine I've ever tended used some oil.
Your wife (or anybody else) "liking the power" might just translate into spirited driving!
All the Volvo and Saab owners who gripe online regarding tires lasting only 20,000 miles (where mine last 50K and more!) suggest they like the power too.

All you can do is cross the T's and dot the I's until you're satisfied. Satisfaction may go all the way up to an engine rebuild.

Maybe get a bore camera to see the cylinder walls' condition when you do your compression check?