The possible troll you speak of has actually riden more XT660s than anyone on this forum will and probably more Offroad miles too.
Meet Greg.. http://youtu.be/dnUzw-U27eA
While you might not agree with his opinion a quick bit or research would save the old "foot in mouth" syndrome when deciding on who's opinion is more valid.
Worth having a little look at his exploits and the ride group he "owns" as this alone sees him and the other owners pre-ride all the tracks and more before leading the group rides.
His current stable of XT660s and he also has two well setup WRs for short runs can be seen on the ADVrider forum...

Check out THIS and THIS just set aside a few days and keep an eye out for TB650 and then you can make an informed decision on his troll status.
Personally I have both air and fuel mod and as a seat of the pants I'm more than happy with the KevMods.