Synpower SM is a 5K oil in our Forester.
I base this upon a UOA of the third 5K run of Valoline syn from the Forester (VR1 10W-30 then Synpower 5W-30 then Synpower 10W-30).
Wear metals were low, with zero lead, but TBN was down to 2 and small change after only 5K.
Synpower SN might do better.
OTOH, I had a great 4K UOA of my third run of Maxlife from my old BMW.
The oil I UOAed was Nextgen Maxlife SN 10W-40.
TBN held up great, at 5+, while wear metals were almost nothing.
What I'm telling you is that were it my Volvo, I'd maybe try Maxlife 10W-40 on short drains.
If you want to use a syntetic, maybe a good idea with the turbo, PP or M1 are longer lived oils in service at the same price as Synpower, while QSUD is also a better bet at a lower cost.
If you can get the Synpower really cheap on clearance and with MIR, as I did, then try it.
For regular price, I'd use either PP or M1, or I'd grab some QSUD and save a sawbuck.
For a couple of more bucks, there's M1 EP or Ultra.