If all you really care about if performance, hard to beat their value. I think sound and looks do matter, but that's more a matter of personal opinion. What I don't like about the Hypers I've seen on Z's that the pipes seem to hang lower, and are not tucked in as tight as other systems. Plus. you've got that weird angle of that cans pointing out the back, which again, is good for flow but definitely lends a "bolt on" look that I don't like.