I have and really like the CFR look and sound. Here is the dyno chart with them. The green is CFR. The other two are fullsac 2" with x pipe. The build is hd 10.5-1 pistons 777 cams and 030 gaskets. No headwork, just cam piston install and tts tune. I have both maps, so in 30 mins I can swap slipons and remap for either sound or preference. Look and sound of the CFR is better, although a lot louder. Long rides get the fullsac for sure.. Just a look at what lots of people with any kind of build say about the CFR, not bashing them at all. Fullsac is a tough combo to beat for bolting on, no matter if it is stage 1 or 2 with his maps and products. good luck, have fun, and enjoy riding no matter what you go with!!!!