I went back today to change the filters and do a followup check and belt adjustment on the unit.
No PD through the SL filter drier, so I'm taking the lazy rout and leaving it.
That roughly 1:1 blower drive ratio is pretty hard on the belt, I had to adjust quite a bit of slack out of it after only 2 months. Looks like I'll have to keep on top of that every filter change.
I put a Gates HighPowerII belt on it, but I'm having 2nd thoughts on that choice...