PTT Youngin$ is described as one of the loudest and most online gangs in Southside. The Ultimate Edition includes a raid on their compound, with special items as a reward if you get away.
The official text: 'Raid the compound of one of Southside Vice City's loudest and most socially active gangs and escape safely to score some special items and distinct contraband.' It is listed as an exclusive side mission.
The other piece of Ultimate side content is the Classic Car Collection: a commission from Wyman, 'eccentric collector and local fixer,' to track down abandoned classic and project cars and restore them.