I've not heard the JR exhaust, but I like my excellent hearing so for me ALL the cobra pipes are just too loud (least the ones I've seen/heard)
My personal preference at this time is stock, drilled out for the A/F sensor on the dyno, but REALLY like the looks of the JR pipes and may switch out to them or something like them if I get my brother to help out with the welding 8)
I like the stock sound, undrilled and plain. I had an incident with a HD rider just a couple days ago. He hauled [email protected]@ through heavy traffic to get up next to me, then gave me a turned up nose when he got next to me. He said something about his being louder and revved his god-awefully loud bike. I told him I like the quiet, I never hear my bike anyway because I outrun the sound. He laughed and gunned his bike, I flicked the throttle to about 4K on the RPM on second gear and passed him. Just about that time, with his bike being very loud, it attracted a local cop who stopped him to have a chat. I "quietly" kept cruising down the road.