Looks much better! I did the same, not in a 2012 but in a 2001 with an evo bumper. I used a Magnaflow, same size as for Camaro's and Firebirds which have the same set up. It is 5x8x18 and run for $104.00.
Pump Gas 385whp 319wtq
Race Gas 551whp 439wtq
Tuned by Fernando@RacingPartsSolution.com