The differences between the RFS 520's are:
MXC has a taller first gear and a shorter 6th gear, with minor changes in between. The MXC has the same lighting coil as the EXC but no lights, a larger tank, and according to the spec sheet I am looking at, they weigh the same. Hope this helps
I was speaking with regards mostly to the 400 E/XC vs 400 M/XC, of which the KTM web site specifications say 236 lbs, and 246.8 lbs., respectively. I can understand a large gas tank weighing a couple pounds more, but 10 lbs?
Also, could someone please respond as to how the suspensions are different, if they are?
The KTM website has been wrong for some time on the weight. They weigh the same according to the specs in the KTM literature I'm looking at, 246.8 lbs. That makes sense, too. The bigger tank is offset by the lack of lights and the lack of the EXC's subfender in back.
The suspension is the same as the EXC. To be clear, the EXC has taller top gears. It'd be significantly faster on top speed, everything else being equal.
Thank you all for your clarification. Looks like the 400 E/XC or M/XC is hard to get right now, and also quite expensive. I am looking at a year 2000 200 E/XC tomorrow that the owner of a suspension shop has. He would set up the suspension for the prospective buyer and it has some extra goodies on it too. He's asking $4700 for it, and he said it's in stock condition. Assuming he's telling the truth about the condition, is this a decent deal?