As far as 'stock' torque and horsepower, here is some information I had saved;
"The 883 runs a 8.9-1 compression and can run on 87 octane fuel, while the 1200 has a compression ratio of 9.7-1 and requires 91+ octane fuel.
The 1200 also uses high flow cylinder heads from the Buell XB line, and cams from the 1200 Sport.
Factory horsepower and torque figures for the 883 are 53 HP at 6,000 RPM, and 51 LB-FT at 4,300 RPM.
Factory horsepower and torque figures for the 1200 are 70 HP at 6,000, and 79 LB-FT at 3,500 RPM."