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 10w30 then Synpower 5w30 then Synpower 10w30).
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.