[Dave at Pelican Parts]

More:

For autoX, your tires become a "wear item"; you will need to get used to replacing them much more often than you would with street driving.

On the Big Track, not only tires but also the "business end" of the brake system becomes wear items--you'll be replacing pads relatively often, and brake fluid all the time. (Because having the pedal go to the floor when you come screaming into a turn in top gear really sucks, take it from me!) Rotors may also become a relatively frequent replacement item.

And there is always the risk of an "off" damaging the car--maybe something as simple as mashing the front spoiler on a berm, or maybe something much more costly. Thankfully, those risks are pretty low and can be managed to an extent.

--DD