Feel free to add your photos of your 2012 bike's exhaust here, it'll take a while for the pictures to accumulate, as it's a relatively new model.
Here are a few photos of exhausts on the 2012 Ninja 650, practically any previous generation exhaust system can fit the 2012 model but the big question which is still waiting to be answered is:-
"would drastically changing the exhausts system on the 2012 model require a power commander, or would the bike be fine with out it?"
I'm 98% sure the bike would, so if anyone happens to have tested a 2012 model's A/F ratio could they please let me and others know
Karl