[DCOTOSAN]

Some suggestions:

1) Good tire pressure gauge. Remember to start at a lower than suggested PSI as the tires will heat up quickly. Change pressures to suit your style.
2) Blue painters tape. Tape headlights, leading edge of hood, leading edge of inner fenders behind front and rear wheels, mirrors, and as much of the front bumper as possible. Looks geeky, but your paint will thank you.
3) Seat belt tensioner. This will lock the seat belt to keep you in place.
4) Move the seat closer to the steering wheel. You will have better car control.
5) Good helmet with good ventilation. Cooler and lighter head will make track time more fun.
6) Check to see if your insurance covers track days. Otherwise look into 3rd party providers
7) Remember, slow in, fast out. Late apex is usually safer.
8) With the Beemer be prepared to change pads, maybe rotors and tires after a few track days.
9) Best mod for faster times might simply be a set of track wheels and competition tires. However, higher g forces might cause oil starvation in the motor.
10) Never block a faster car. Let them pass. Follow their line (if similar car) and learn.
11) Do not engage your parking brake between runs. Just put in gear and raise the hood.

Have fun. I miss track days.