No worries, I'm probably going to add an option to turn off the damage/wear.
About the damage/upgrade system: it's heavily inspired by the original mode of Super Hang-On for the Genesis. You could also wreck your motorcycle, repair and upgrade it. Only difference, you had to earn money, while I prefer the time management system borrowed from the World Rally Championship. The limit on the amount of parts is simply there to prevent players from replacing good parts.
About the engine sounds: don't forget: I made this game like Kazunori Yamauchi made the first Gran Turismo: to suit ME. 😆 But I'm going to add a save system for the option menu so you don't have to readjust the engine volume each time you turn on the game.
You can also play the Outrun mode where you don't have to worry about damage. And if you don't like branching paths, I'm probably going to add an extra game mode where you drive from point A to point B.
The green bar represents your brake temperature. Once it gets above the black bar, you lose brake power. It's mainly there for me to monitor the brake temperature for fine-tuning purposes. I'll add the option to turn it off.
Color selection is going to be added if I figure out how you can replace the color in the UI. At this moment the cars turn completely black if I try to change the color in the menu. That's the only reason why you can 't change it at the moment.