I have a 2011 Overland with Skid Plates. I just installed the Corsa exhuast. I did it by myself in the ORII setting and lets just say its a little challenging to do by yourself
Theoretically it should fit with no modifications. Mine was sitting slighting to one side (despite my efforts to adjust) which caused a little rattle between the exhaust and the skid plate. I ended up taking it to an exhaust shop where they cut a small piece of my plate off to stop the rattle and also re-welded the rear hangers. The were sitting horizontally with a little too much stress instead of hanging naturally (vertically). 15 minutes later and $30 and all is well. No rattles and the sound is amazing! Exatly what I wanted and a great match to the Volant CAI
I'm not sure if there are any major differences between the 2011 and 2012 that would cause a different experience.