Originally Posted by Fawcett
...We use the grass trimmer attachment but a dedicated trimmer is much preferred. The unit isn't as balanced as dedicated trimmers, the trimmer shield is too big and the clippings clump often. ...
Huh? The straight shaft trimmer attachment uses the same parts as the gearbox at the end of a Stihl straight shaft pro trimmer. Same gearbox, same line head, same guard, same everything. The only difference between an FS100R with a straight shaft head, and a KM100R, is a few ounces for the clamp.
If you have the brush cutter guard, which is the oversized guard made for use with a blade, I can see that having issues with clumping grass. That guard also does not have a line cutter built in though.