No one's going to warrany a car that you beat the shit out of, whether it was built to have the shit beat of it or not. It's just not good business.

The speeds you hit in autoX are lower than public roads, but you're driving the car considerably harder than you legally can on a public road. It doesn't matter how fast you're going, you're still increasing the chances of your drivetrain/suspention failing.

If you owned a car company, sold a car to an 18yo kid, the kid went out and drag raced it and autoX's it, then blew a piston, you sure as fuck wouldn't want to fix it either. So shut up.