Are you talking about these guys http://www.ncracing.org/events.php
These guys have an event Sun the 19th as well as the 25th and 26th. This is who I run with and it's definitely an HPDE. No timing, passing only in designated zones (except open/race groups), instructors available, etc. If you can't get insurance for their events you could try hooked on driving on the 30th or track-masters on the 31st. Both are a little more expensive, but they offer instructors to every driver if desired for the entire day. The only thing is you'd have to check their rules on convertibles. They are both super picky. If I'm not mistaken they require full roll cages for open top cars, but I'm not 100% on that.
On the track you'll find the suspension and brake stuff to be hugely rewarding changes in this car. It'll negate a lot of the understeer built in to our cars. Good luck and let me know if you decide to head up here. I always love seeing other 1's on the track since their are usually 25 m3's to every 1 series