Scott... Here's a 944 Autocross video for you.
I seriously caught the bug a few years back and spent a good sum of money on upgrades and what not. I'm running RA1s now which really raise the limits and make it much more fun. Also much more money.
But take your miata bone stock and you will have a blast! They are fun little cars to drive in anger, and it will surprise you how well a good driver can shuffle one around the track!