Ok, I'm from Mexico City. I'm a chilango and I read this...I'm afraid this translation is not accurate.

Chilanga Banda literally means Chilanga Gang yes, but he means "People" meaning all of us not a "Gang". The song was not written by Café Tacvba, it was written by Juan Jaime López, another musician and I think it's a wonderful song. Here's a more accurate translation or more like an interpretation of the song... and I fear that it's gonna have to lose all the slang...chin.

Stop it chilango! (guy from México D.F.)
What a bad job you have
The suit and tie don't fit you
and knock it off with the badge (stop showing off)

As fat as a bed bug
More corrupted than contraband
With gun and night stick
you could pass as a bodyguard

I better go for a beer
and with luck I'll get a girl
Working as a taxi driver
I got plenty drink and party

If I crash in my car
police is not very friendly
Screwing those who infringe
is how they make their living

At night I crash at the whore house
Come on! says the "lady" (jajaja)
To the bunch of drunks:
Quickly, pass me the weed! (bacha=marijuana cig. bud)

(Chorus)
Pachucos, cholos and chundos
foul-mouthed and badly dressed ones
Here the bad ones rule
and they have a really good time dancing (tibiri-tabara)

My buddy finishes smoking our weed (bacha)
And sings La Cucaracha (song about running out of weed)
His head lives of pills,
glue, weed and junk food (street food)

Robbin' here and there
There it is the "chilanga banda" (people from Mexico City)
Beware if you insult my mother...
... cause it's gonna go back at you.

Notes:
"Banda" how friends call each other in the city.
"¡No manches!" is an expression of discontempt or disagreement, same as "¡Chale!".
"Chundo" is also a word for poorly dressed people.
"Tranzando" means to "cheat" on people to get money, not to mug them.
"Chin chin si me la recuerdan" it's: Go Fu** Yourselves if you "remind me of my mother" (which is also a "Go Fu** Yourself").
"Carcacha y se les retacha" it's "Car and crashes back at you"

If I would explain more I would end up translating this song twice, I think you get it by now. Cheers

-A-