I run the 3" Dyno-Max Ultra-Flows and I like them. They are not way to loud but when I hit it they sound almost like open headers. I always race my 63 capped up and it feels good with the straight thru Ulta-Flows. One day I may uncap it but I really don't think it will be much if any faster. I actually went with the Ultra-Flows for the best performance rather then how they sound as I knew this lazy old man was not going to crawl under my car at the track and uncap it. Ron