Here it is! This mod features both the POSTAL Redux music and a special bonus for the Stealth part.

Stealth: POSTAL 1 OST - The Ghetto (Edited)

Control: POSTAL Redux OST - The City

Anticipation: POSTAL Redux OST - Clap To Death (Rampage Mode only)

Assault: POSTAL Redux OST - Blood Path (Rampage Mode only)

Note: I might replace The City theme with something else from the game's soundtrack if you're feeling very uncomfortable with this creepy track.