AZ,
installed mine two weeks ago its a huge difference from the previous ride, i pulled my blower off for the Apten mod (after the AZ Dyno day) so when I get my results back after a tune I will post it, also went to a muffler shop specializing in aftermarket stuff and they charge 100 buck to have them installed
i had mine put in a couple of weeks ago .. wish they were the first thing i ever put in the car .. huge diffrence .. ill never own another vert without them