Re: T-shirts - Silkscreen is a rather quick thing to set-up, as it crappy print and Iron set-ups. I wouldn't call those shirts 'quality' in any sense.
The gang culture is such an odd mix of elements. You have feudal codes of honor, vengeance, and fealty (even if folks don't recognize them at first, they are there) while at the same time you have various forms of apprenticeship and 'entrepreneurial' crime. The big difference between Gang culture and Mob culture is age and suits. It's the younger kids who are more territorial and spoil for violence.
Look at some of the ways gang members rehabilitate when it occurs: Clever and ruthless businessmen, military soldiers, community reformers and leaders. I despise that there is a culture of crime and violence, but the real shame is the diversion of such talent into bloodshed and vengeance.
I hope that the family, instead of calling little Leo 'gansta' and raising her in a role to facilitate vengeance and hate through violence instead raise her to take become successful in school, business, and buy the whole damn neighborhood and kick the bastards out, or become a cop and bust them.