Whenever I enter a car it keeps on looping some kind of screeching sound as if it were constantly drifting around corners or something - doesn't matter if I drive the car or let it stand perfectly still in a parking lot. Anybody else experience that? :(

Yes, had to reinstall the game to get rid of it. But even then the PC version is a broken mess as there's an infinite amount of bugs, glitches and random crashes waiting for you if you decide to keep playing regardless. I gave up on it and am now revisiting the Xbox 360 original myself because the PC version just isn't a fun experience.

* Bad audio mix and brake sound while in a car with 5.1 audio

Switch from surround to Stereo sound in Windows.

From PCGamingWiki.com

Thanks, something like that actually did it. My speakers were mistakenly set to Surround Sound - fixed that and it fixed the problem.