I've been to Spring Mountain 3 times for the ZR1 school (my 2010 ZR1), then Level 2, and Level 3. Rick Malone said I set the student lap record each time I went.

I can wheel a car enough to know I'm not going to tear up my CT5-V Blackwing on the track even if it could handle the abuse with better brake fluid. I took my old 2012 CTS-V to the track once (Eagles Canyon in Decatur, TX) and within 10 minutes, I had cooked the stock brake fluid (my mistake), stock brake pad material was breaking up, and lost all brake pedal causing me to slide off the track at 50mph, but luckily threw it sideways in the grass and slid to a stop a good 10' from the tire wall. Good times.
I'm going to LOVE driving my 5BW around town, but it will unlikely see the track. I have other cars more suited to the task.
I will definitely be taking the Spring Mountain school though to beat on their Blackwings. Love that place!