Heres the info on all the gangs of GTA 3.
Columbian Cartel
Leader:Unknown
Area:Cedar Grove
Clothes:Cowboy Boots, Jeans, Printed shirts, and Rimmed Hat
Car:Cartel Cruiser
Radio Station:Flashback FM & Rise FM
Diablos
Leader:El Diablo
Area:Hepburn Heights
Clothes:Denim, Red Bandanas & Slick Black Hair
Car:Diablo Stallion
Radio Station:Head Radio
Leone Family Mafia
Leader:Don Salvatore Leone
Area:St. Marks
Clothes:Black Suits, Black Sun Glasses
Car:Mafia Sentinel & Limo
Radio Station:Double Cleff FM
Southside Hoodz
Leader:Unknown
Area:Wichita Gardens
Clothes:Gold Chains & Rings, Red and Black Jackets
Car:Hoods Rumpo XL
Radio Station:Game Radio & MSX FM
Yakuza
Leader:Kenji Kasen
Area:Torrington
Clothes:Stylish Suits, Deep Red or Blue
Car:Yakuza Stinger
Radio Station:Lips 106 FM
Yardies
Leader:King Courtney
Area:Newport
Clothes:Tan Jacketsm Black Shirt
Car:Yardie Lobo
Radio Station:K-Jah FM
The Nines
Leader:Unkown
Area:Wichita Gardens
Clothes:Blue Jeans, Purple & Black Jackets & Backwards Caps