TBAG,
A little less than twice as loud, under throttle conditions; at idle only a little. Put it this way... I ride with a guy who has a 107 S&S motor in his chopper, and with the stock 16Ga's I couldn't hear anything, even what gear I was in. With the V-Moded baffles, I could. Not too loud at idle, but when "raked", watch out! Sets off car alarms!
As for the map I run, she LOVES this one:
M809-018 - Screamin Eagle 16 Gauge Double slip-ons (without baffles), Stage 1 ECM and Screamin Eagle air filter
Great all-around performance!
Mike