Thanks for playing! The idea behind stopping each lap, was to make the acceleration upgrade more appealing, since you're mostly taking corners at top speed anyway. So faster acceleration increases the $/s. But stopping every lap also feels bad, so this led to the lap upgrade. This two things work a little bit against themselves. If I had more time I would have wanted to balance game in such a way that braking/acceleration plays a bigger role, so laps aren't necessary to make those upgrades shine.
Yes unfortunately I didn't have time for any sfx, should have paced myself better.
Again thanks for playing and the feedback.