Not a definitive answer but they both have the Siemens Contitech ECU. I believe you can get the ECU flashed as necessary on any of the models including with or without ABS, exhaust flapper, etc. You could call one of the places that does rexxer reflash and ask them. Exhaust is different between the engines (at the header as well as the pipes setup under tail vs side cannon). I don't know about the engine mounts...
I have my rebuilt M1100 S engine (heads, hi-comp pistons, bearings, flywheel, etc) with Tuneboy and autotune, with just a few thousands km's on the clock sitting in the garage. I could part with it for the right price. Beast of an engine. PM me if interested
2009 1100S Termi slip-ons, hi-comp pistons
2012 M796 (Tree'd)