I run the KTM PowerPart Akrapovic exhaust with the baffle and I find the noise level OK. I also listen to XM radio on my commute, and with my Shoei helmet it's the wind noise that gets me around 75 mph rather than the exhaust. I took a ride around the neighborhood without a helmet after breaking in the slipon and it doesn't seem to loud to me, at least not at WOT, compared to my FMF Q4 on another bike I have. Fits the bike well, I think. (What did surprise me is how snappy the shifter clicking is!)
Here's my helmet lock solution. At least it is something to do with the free locks they throw in with the purchase of a handgun.
Taken before the slipon arrived. (And I wonder why it rotates images that are uploaded?)