When i got my exhaust done on my 2010 i went in with the attitude of sounding like a 5.0 Mustang and wanting 3" Exhaust...i was shot down very quickly. It will be way , way , way to loud and you'll get crappy gas mileage. So i asked what the best was...2.25" or 2.5"...you can then get tips welded on from that are pretty good size that doesnt even look like a tip...i got the flow master series 50 with 2.25" piping and love it!
http://www.flickr.com/photos/11733708@N03/4933035869/http://www.flickr.com/photos/11733708@N03/4933035869/ by JZ Photography
, on Flickr