assuming that it's still the original clutch, it's probably just worn down and will need replacing soon. however 81k seems a bit soon for a clutch to wear out. it all depends on how the previous owner drove it.

i wouldn't worry about floating a valve since you caught the rev limiter on the way up (in other words, it wasn't a misshift). if it's idling just as before, assume that it's ok. if you really want to put your mind at ease, you can do a compression check or leak down test to be sure. however, not to freak you out, this may uncover problems that you've had before, so if things don't check out, it doesn't necessarily mean it was due to the run at the track.

what i would do is check to see if it is the clutch that's slipping (and due for a replacement). there are a few ways to check this, though i'm not versed on all of the methods. i've heard that one way to check is to punch the gas while cruising in fifth. if revs climb with no apparent increase in speed, your clutch is probably slipping.

anyone else want to chime in with some methods for clutch wear check?