Autox is so much fun. I used to Autox an 89 CRX and a 2000 Civic Si back in the late 90's to early 2000's and gained a lot of hands-on experience in car control and the limits of each car. I ran both SCCA and NASA events at Giants Stadium, Camden Waterfront, Nazareth Raceway infield, a mall lot in Wilkes-Barre, and even an old deserted go-kart track in Carlisle that was like a mini road course, barely wider than the width of a car. Where else can you drive your car at 10/10ths legally for so little money without worrying about jail time? BIG fun.
I was very competitive in my vehicle class with my Si with very limited modification, but I stopped racing when I got my '00 Audi A6 2.7T in 2004. It was too heavy and just not the right car for such duty. Then in 09 I got a Volvo XC90 V-8, another car not meant for this. This March I finally got a car worth bringing to an Autox, an '11 GTI. Hopefully I'll get the time to get back in the cones in the future.
Some random thoughts-
-Slow in, fast out is the best way through a curve, but its hard to get that in your head when the clock is ticking. That takes practice since the initial thought is charge the turn and brake way too much and slide the front tires.
-Look at the course and imagine a smooth route and plan things out, give up speed in a slow area if it means a fast exit and gains in a higher speed area of the course. -Smoothness is key, avoid unsettling the car with jerky movements.
-The handbrake is a friend and can be used to rotate a FWD car when needed.
-A lot of times the fastest guys aren't squealing their tires as much as the slowest guys, they know their cars strengths and are keeping their car in balance.
-Try running a gear higher through some turns to change the attitude of the car, many times it results in a faster time even if it feels slower.
-Tires make a huge difference, I was given a worn set of 140 tread wear tires and they stuck so hard I couldn't stay in my seat. They were glued to the track.
-Talk to a lot of competitors, even if they drive what looks like a beater they may have the same car as you at home and bring it to other events and could have good info. -Get an air storage tank (basically like an air compressor without the pump, just a tank you fill with a compressor) that can be used to raise tire pressures as needed.
-Tire pressure front to back can totally change the way a car handles. Stiff (high psi) back tires will allow the rear to turn faster, and softer (lower psi) front tires allow more grip. On cars with more sidewall to the tire we used to use white shoe polish and mark the sidewall in 3-4 spots. If the polish was worn off you add air to that tire, if its all there (the shoe polish marks) bleed some air out. Its a good way to see if the tire is getting used to its fullest. Not sure if the super low profile tires of a modern GTI would benefit much from that.
After a day of pushing yourself so hard you'll end up driving a bit slower on the streets and you'll start to pay more attention to little details as to how the car handles and feels, in preparation for the next event. What you learn will last a long time, its been 9 years since my last event and I still mentally take notes as to how the car responds for max performance in case the situation arises.
Have fun!