I'm leaning toward the Corsa system as well. I have a '96 Vette with the LT4 engine, I purchased a Corsa cat back system for it and WOW what a difference. Awesome sound at full-throttle and whisper-quite ride at cruising speed without any in-cabin resonance. It took me a little over 2 hours to pull the stock exhaust off and install corsa system, granted I had access to a hoist. The system was very easy to install and everything fit togeter perfectly. Even though the corsa system for the GTO isn't duals, it still increases exhaust flow by 85%.