Thats good info to know. Thanks for passing that info along. I run the Ultra-Flows but I use an H-pipe and not the X-pipe so I dont know how well mine works. I may pick up a tad uncapped. My Ultra-Flows are not real loud unless I am on it hard. I can and do listen to my radio while driving and right now I only have the dash speaker. Is that a 3" system ? Ron