I am making a racing game on Unity, and this physics engine is too realistic for it. However, I do find the sounds quite good. Am I allowed to use only the sounds (with proper MIT-abiding attribution, of course)? Also, were those sounds sourced online, or did you make them yourself? I don't see any attribution.

Yes, you are allowed to use the sounds for your Unity project. The sounds are designed by me using a music software, Caustic 3.2.

Apologies for the late response.