I was the only "vintage" car that showed up, unless you count a 944 or mid-80's 911. Drew some attention. Had two female drivers enthusiastically tell me that my car looked "so cute!"
Lots of Boxsters, Caymans, 911s, including a couple GT3s.
The morning was spent in various exercises, accompanied by an instructor. First up was the skidpad. I was surprised how much / how long I would understeer - almost had to try to get the back end loose. Did get some good practice recovering from having the rear end come around.
Next exercise was threshold braking. Funny, as I was probably the only car without ABS. Enjoyed that. Ate one cone during the combined brake-swerve maneuver.
Third was a slalom. I got probably 8-10 runs at it. My instructor had once owned a 914 and really encouraged me to hoon it up, taking big, wide turns and getting the back end loose. It was a blast.
After lunch, there were lapping sessions with an instructor in the car. First session, I had a hard time finding my line through turns 1-3 and turn 7. Was running WOT for about half the track and holding my own. Got passed by a few other drivers in Boxsters, Caymans, a GT3, etc. Then, on my best run through turns 1 & 2, I lifted too abruptly in Turn 3, nearly saved it, but sailed backward into the mud inside of turn 4. Chalk it up to learning experience and wanting to pack some souvenir mud into my wheelwells.
Second lapping session, I rode shotgun with my instructor in her Boxster. This gave me a much better feel for the racing line.
Third lapping session, I intentionally started last in my group to save others from having to pass me. We were out for a while - probably 15-20 laps - and I really found my groove. Not every lap was perfect - far from it - but I was squeezing all I could out of that 2.0, stock brakes, and skinny 165 tires. I think every car in the field lapped me, but only because it was so easy to catch up on the straights. I even pulled away from a Boxster S and a Cayman through the twisty sections.
All-in-all, a great experience. I have no intention of getting into DEs or even Autocross, but it was a great chance to get more familiar with the performance and feel of my 914. Not to mention, about as much fun as you can have with your clothes on. Highly recommend doing something similar in an event where you can drive your own car.
On the downside, I think all that time spent at/near redline exacerbated what was once a very small amount of oil leaking.
Other notes:
Met MikeSpraggi for dinner - great guy!
Drove through constant rain, much of it heavy, on the way out to Summit Point. Besides a weak defrost for the windshield and a moderate trickle of water intruding on the passenger side, car did great on the drive out.
one day, even if it's on the street! 
Glad you had fun. It is tough to drive a car with double-digit HP against all those newer models; I get passed so much my passing-signal arm starts to hurt. If you want to be in the fast drover crowd, all you have to do is open up your check book but that would not be satisfying to me at all. Maybe I'm just an old grandmother drover and am satisfied with my speed (or lack thereof). I really like my car even if it's not fast enough for those who bought a GT3 for their first Porsche . I couldn't imagine spending my kids college tuition on a car. Don't rule out doing DE's, just get another set of wheels and put larger tires on; you can still use the 165's at the concours