It's a BIG investment of time and money, as I'm quickly learning. Plus you get a fraction of the track time compared to HPDE. But it's fun as hell, and your driving skills jump by leaps and bounds when you're constantly probing the limits of adhesion with cars in very close proximity (inches away).
I was down at NJMP last weekend doing recon with the Audi club prior to racing there in the next few months. That's a very cool track too, Thunderbolt. You should try to get up there this year to check it out.