I owned the 2011 350 Sx F for 5 years,, had no problem with fuel pump.But did have a recall on the crank bearings and was upgraded at n/c to a electrical plug in harness that did something with the injection. I purchased it in Aug 2010 and used it for woods riding only. In May of 2011, the 2011 XC F was released. I wish I had waited for this model.(it had a bigger tank and headlight) Then in 2012 the exc xc and Sx had motor upgrades were KTM increased the motor 7 horse power.
I'm now thinking of purchasing the 2016 or 17 EXC in the spring .. 350 is the way to go, I rode a friends,for 2 days, off road last week. It was awesome.