Braking practice in a 6 was a waste; it's just an opportunity to experience ABS and learn you can still steer under hard braking.
Slalom in a Mazdaspeed Protoge was marginally useful. The Protoge itself was a nice car but how much can you learn on a three cone slalom?
Practice in a 6 was very useful but unlike the other two courses you can only practice twice.
If you attend my recommendation is go early and attend the first Chalk Talk you can (you can go to an earlier session if there's room). Do the braking or slalom if you want but try to do one practice just before your first timed run. Then do your second practice just before your second timed run.
They had a go-kart course that cost $10 for 4 minutes. Pricey but fun. The "track" was too narrow to pass easily but you could stand on the throttle through the chicanes and drift in the sweeper. The only time you had to hit the brakes was for the hairpin at the other end.
The 6's have aftermarket springs, tires and exhaust. You can "manually" shift the automatic transmission to keep it in 2nd during the run. I'd recommend shifting at 5k; any higher and you'll hit the 6k rev limiter before it actually changes gear.
I attended sunday. In the morning they had people get into a cheesy Sparco four point harness for the timed events but gave up after a few hours saying it was taking too long for people to adjust the belts. There was a problem with the timing system--lap times were shifted one position so you were given the time of the person who just finished before you. I'm pretty sure it was off during my first run at 10:20 but since I wasn't positive I let it slide. My second run at 11:40 was decent (pro index time of 33.600, my run clean at 35.007) but the printout showed 37.6. I talked with the chief steward and we reviewed the lap time printout. I spotted the shifted lap times and fortunately there was another competitor who came up to complain at the same time so we had some credibility. The steward said it was an isolated incident that only affected a few people but I'm pretty sure the problem was there in my first run as well. The lesson here is memorize your time shown on the on-track display, compare it to the printout and make sure to bring it to the steward's attention if the last three digits don't match.
If you've never autocrossed then $40 is a fun way to test the waters. But it doesn't compare to SCCA events where you spend less, get more laps and are probably driving a better car.