I worked out the issues I had with V-sync and screen resolution. But now I can't steer any of the vehicles left or right. I can move forward, but the steering sensitivity is far too low, making driving useless.

So here's my question, is there any way to fix this problem? I'd be very grateful if anyone has a solution.

Okay, I figured it out. I just had to set the value of VSync from 0 back to 1 again in the AlienShooter.cfg file. Surprisingly, no frame rate issues so far, knock on wood.