Legend of The Afterlife

Street Cred is a form of rep/XP, given by completing various activities on the streets; side-quests, random encounters and such. The max level is 50 - which you'll easily reach by mid-late game if you're generally participating in everything going on, which you'll need to be for the other achievements anyway. I.e. no special effort is required here; you'll end up achieving this through natural play.