[radz28]

While I haven't had either catback, from either company, on this car, I have had catbacks from both companies on other cars ('95 and '02 Z28 [Borla adjustable] and '05 H2 [Corsa Touring & Corsa Sport]). While these are different cars, the muffler technology in each, I think, has consistencies through their respective line-ups.

Having 2-cars with Borlas (and hearing many with Corsas at the track), I'd say that the idle was pretty subdued, and the pulses smoothed out with throttle. I never got drone on the freeway and, with LTs, I think the exhaust sounded better with the cutout closed (i.e. that there was refinement and not just a bunch of rasp on the throttle with the cutout closed). It was a clean, loud, but nice sound.

The H2, which I had with a stock 364, a 370 (with an LS3-type top end and a Cheater cam), and a 408 with an LS3-type top end and a BTR Stage IV cam), had a louder idle and shrieked on the throttle. The pulses were more staccato and the Sport muffler was definitely more raspy. However - there was nearly no drone, and what little there was, was more white noise than anything.

I think LTs and either catback will be considerably louder but you might try to find video clips and get a reference. RPM-videos showcase a lot of combinations that might give you something to go off of.