I've noticed in online races at the starting line when the other drivers are revving up the pitch of their engines is extremely high, like ludicrously high. It sounds like their rpms are impossibly high. Are they using some exploit you can do via tuning?
No, the way PD made sound appear from a distance from other cars is screwed up. They're not hacking. Sometimes you can hear their speakers through the headset and it sounds like it should, simultaneously.