When I was a teen and putting $ into my car stereo and not safety items, my dad would say I wore the tires down until "the air was showing". I'll never forget it. He would take the keys until I put new shoes on it, then he didn't care what I did. Safety items were first with him, no matter how cool or not my stereo was. I had 15" subwoofers in the back hatch and could not see out the back, he could care less. Tires, brakes, lights, and wipers good? Go have a good time. Love you dad.