both companies patent contracts are up
go to a local shop and i guarentee you they have an exhaust system that replicates at least one of them, and its at a fraction of the cost.
I have the GM performance exhaust/intake on my truck. Its not roaring loud, but sounds good and gets throaty when you romp on it.
However, i would probably go a gibson dual sport exhaust if i were to switch it up, but i got a 75% discount on the GM parts //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif