I've had one of these bikes for a couple of months now and ridden about 2700 miles so far on it. This is the first street bike I've owned/ridden and I love it. It rides like the dirtbikes that I'm used to and handles like a dream.
I've had the hard start issue once in a while and at first thought it was the battery being low but I ride the bike a lot and doubted that it wasn't gettin charged. I tend to think now that it's caused by the engine shutting down on a compression stroke and having a hard time dealing with it. I will check the connections at the starter though after reading here.
I also used to have the stalling issue but recently regeared the bike with a 15t front sprocket and this has given the bike whole new life. It's way more fun to ride it pulls like mad on the bottom end and I never stall out anymore. After riding the bike with the 15-40 gearing I can't believe that KTM shipped these bikes with the 16-40.
Like everyone else I'm in the market for an exhaust. I'm pretty sure I'm going to find a way to get the Akrapovic. From the videos I've seen online of these systems on other bikes the quality, fit and finish seem to be top quality. AND IT'S TITANIUM!!!!

I'm pretty sure you coule run the Supermoto exhausts on these bikes. You'd just need to get the muffler brackets from the oem but I don't know why you'd do that. To me the dual exhaust on the Supermoto is fugly.
What kind of tires is everyone running? I got about 2500 out of the rear before it started showing cords. I was hoping to get a little better than that but the tire was super grippy. Currently I have the factory tire up front still and just switched to a ContiSportAttack on the rear. I only have a couple hundred miles on it but so far it seems quite a bit harder and a little less grippy but we'll see how it turns out for mileage.
Corey