I'd like to clarify a couple of things for you guys regarding the GM Borla exhaust system. Yes, I have one. First, Borla does not sell this system directly. The GM Borla (Performance) exhaust system is sold through GM dealers and their web sites. For example, I purchased mine from Banner Automotive through their Amazon store. In August 2015, my purchase price was $1,020 plus $144.95 for the chrome tips kit. The tips are extra (not included in the kit) and come in chrome or black. According to several GM Accessories sites, the normal GM tips do not fit this GM Borla exhaust system.
It is a very high quality, easy to install cat back system. One of the differences from other Borla exhaust systems or other manufacturers is that it includes a Passive Exhaust Valve (PEV, aka "flapper") that appears to be of higher quality than stock and is mounted on a bypass to the main exhaust pipe (think of having a loop attached to the main pipe with the valve inside) which eliminates the restriction, but helps with AFM/DOD noise. The sound is compared to a "Touring" sound, so if you were to go to Borla's web site and listen to the "Touring", it would be close as compared to "Sport" or "ATAK".
Another note...even the Corsa exhaust systems for these trucks is more expensive now than they were a few years ago. I too was surprised. I am not intending to start another "exhaust system bash" thread, but just wanted to share my experience with purchasing my GM Borla exhaust system. I wanted a complete system and all that entails. I normally install exhaust upgrades myself, but had Midas do this one since it was over 100 degrees here, in Texas, when I bought it.