Got rid of those spring things plus all the other extras? in the stock L99 vert exhaust!!!
I installed a stock LS3 exhaust along with the SLP loudmouth I on my L99 vert and I love the sound. There were absolutely no fitment issues what so ever. It is significantly louder and better sounding then the L99 vert exhaust was with the loudmouth I. Love the sound!
Below is a link to a picture showing the difference between the two. There are lots of LS3 stock exhausts out there being thrown away that could make for a very reasonable upgrade over the stock L99 vert exhaust (probably the L99 coupe too). Got mine for $100, thanks again Mike!
http://www.camaro5.com/forums/showthread.php?t=138508