I have a list written down of all the gangs from the first two threads and the areas they inhabit. I'll post 'em here, tentative suggestions marked with a question mark:
Big Nasties [Sewers/Themepark at Night], Rozenkrantz [Themepark], Bodhisattavas [Shangri-La], The Volcano Gang [Mt. Vulcan], 9-Ball [none], Bibliotheque [St Altitude's Archives], The Crazies [Peak Clinic?/Supersonic Tech], High Fliers [Skyhigh Apartments], Blackbirds [none], Fireworks [Warehouse District], Flower Children [none], Spice [none], Deadmen [Barrios/The Walled City?], The Inspired [Central City?], Black Roses [none], De Cuisine [none], Guerrillas? [Little Venice], Plumbers? [Sewers/Little Venice], Speedfreaks [Rolling Hills/Route 249], The Neons [High Roller Neon St.], Urban Tribe [Great Temple], The Medics [Newtown], Mall Hooligans [none], Punksquad [none], The Balance [none], Sandmen [none] Valdez Crew [Docks].
I also have a list of the named districts, but they lack descriptions so there's not as much flavour. It was mainly to try and picture how the city would fit together- for instance, Carver Canyon. with Carver falls at the high end near the drained reservoir (where the club Momentum is located), the warehouse district over the Carver Bridge, and the Docks on one side of the rivermouth and Little Venice further down the coast.