Another Indy rep here. The "sir" stuff is a southern thing, brought up here from people who migrated from Alabama, Tennessee, Georgia, etc. ~70 years ago. The only people who really get incensed if you don't call them that are usually entitled old coots, so one doesn't need to think about it too much.
There's also not a lot of farm/redneck stuff around here either, since the incorporated city grows by a considerable amount every five years, and we get our horsemeat from the same labs that you guys use across the pond.
Broad Ripple is probably the most liberal/"arty"/party-centric area around here, and has some nice restaurants. Same deal downtown since there about five or six colleges there.
If you like grease, try the Bar B Q Heaven on MLK street. Place has been around for ages and food critics love it, despite having much more affluent competition downtown