You can drift all you want at the SCCA auto-x. Just be nice to the course workers and don't knock a lot of cones in the process.

The PCA course usually has a ~50" radius 90 degree turn (a low traction turn I must add) that allowed me to do some serious drifting with the porsche last week. Not something I would usually do with a tail heavy car but the big fast turns made it fun and easy.

The PCA events are also $20 as compared to the SCCA's $30 fee for non-members.