Not to scare the op or spoil the party but iirc, SonOfJoe said API SL is not as harsh on seals i.e. it's more seal friendly!
I kind of remember that because at the time, I was considering some 0W-30s (Castrol?) but it was API SL (i.e. old classification). He talked about it being Full-SAPS ... and also more seal friendly!
Not sure if I asked or can't remember how API ratings can have an impact on seals ... maybe due to chemical compound amounts, limits, or lack thereof. I assume they all should pass some sort of seal compatibility test(s) but some may do better!
If I can find the discussion, I will attach the link.
Having said that, I read that API ratings are backward compatible and maybe hard(er) to find API SL ... so theoretically, op should not worry!