So,
I want to get into playing Necromunda at my
FLGS, but I'm a cheap

and want to go with something kind of cheap. I'm thinking of using a Cadian boxed set and doing up an
IG themed gang. I've even got a few minis I've painted here and there for Dark Heresy to use as higher ups in the gang. What I'm not sure of, though, is which gang ruleset would best fit the
IG. Anyone have any ideas?
Also, does anyone have a good tip for converting an auto cannon or heavy stubber?