I finally put the Supermeg on this weekend. I was totally happy with the performance of the Fatcat but was looking for something a little bit quieter. On blipping the throttle and on highway acceleration they sound about the same volume. The Supermeg has a deep rich tone maybe even a touch lower than the Fatcat. On steady mph cruise speed I think the Supermeg may be a little bit quieter which is what I was going for so I could hear Pandora. I just went for a short ride but the performance seems pretty equal. Most after market pipes say "10% improvement over stock" or something like that. Supertrapp says "15% improvement over stock". Since I can barely tell the difference between the 2 I will self tune using the sparkplug method: black is too rich, white is too lean, tan is just right. I put on all 20 discs so there is only 1 direction in which to go. I much prefer how the Fatcat attaches to the bike. It just seems more secure. I'm going to repaint the Fatcat with manifold paint then in a year or 2 when I feel like I have to do something to the bike I'll just change them back on. I feel like I have 2 of the best pipes to choose from.