Etrailer.com had all kinds of 2 inch receiver options for the 2010 OB. I went with the Hidden Hitch and used the OEM install approach so I didn't need to modify frame rail holes for the bolts. This involved popping the rear bumper off and slipping the backing plates and bolts into the sub frame via the open ends behind the rear bumper frame which I removed. Takes longer but I didn't grind or modify the frame in anyway. I specifically went with the 2 inch receiver given the attachment options for the 2inch hitch are way better.
I paid $207 for the hidden hitch 2inch. The only slight modification was a very small trimmed part on the heat shield bolted to the bottom of the car above the muffler. Easily done with some beefy sheers the trimming simply makes a little room for the forward section of the hitch bracket and to prevent rubbing no real concern about side effects for the small modification.
The rest of it all fit as designed no issues. The hidden hitch bracket is not close to the muffler and is a smaller more compact unit which does not pass over the muffler it is exactly the same width as the frame rails.
As for doing the adapter - avoid them - they add wiggle room and result in a loose floppy bike rack which is just bad in every way one could think of. The Hidden Hitch has two holes in it one for the proper pin and the second for a proper bike cable lock which I thought was a nice touch. The main use for my hitch so far is towing my boat - but eventually we'll be getting a bike rack for it.