don't have a response on your exhaust dilemna, but I just wanted to chime in here and let everyone know that I just put on the Cherrybomb V8 kit on my 2011 v6 LS auto. Paired with the KN intake, I love the sound! It is quite a bit than I anticipated with only a few very slight alignment issues, I was done in less than an hour and I got it from
www.performanceexhaustplus.com I ordered it on a Friday which was veteran's day and it got here by thursday the following week!! Pretty awesome since they didn't charge shipping and/or Tax!!!! You guys really need to price them out before you buy exhaust! Someone else has already posted videos and sound clips of this setup in this thread.