[BoxsterSteve]

Cosmo, are you still experiencing this?

This sounds like what I'm figuring through currently. The car threw a CEL the day I put it into hibernation, so I cleaned the throttle body, figuring the rough idle I was experiencing at the end of last season was from a dirty throttle body. I probably should have pulled the fault code, but didn't.
I did the 100k service over the winter. It started right up, but I couldn't drive it until just last week.
The car idles well enough, maybe a touch less silky than previously.
I'm thinking a MAF that's on its way out. The car hesitates wickedly below 2500rpm with a noticeable lack of power, and it sounds like it is backfiring through the air box until it gets rolling. It and starts to pull at 2500+ rpm.
No CEL, though.
I unplugged it and am going for a spin later to pick up my son from work. From what I understand, if the symptoms don't manifest with the MAF unplugged, then it confirms the MAF is bad.
I'll post back with a report.