I've seen the STS do a fair job with straw in small grains like wheat, barley, and oats, at least by rotary combine standards. The STS rotor does not have an aggressive separation section (with the cast tines and expansion area above the rotor). A great deal of the straw damage that does occur comes from either the feed accelerator beater at the front of the rotor and the crop's transition into the lengthwise mounted rotor, or at the rear discharge beater. I've not heard of anything being done to the rear beater, as it is probably best left alone so it will function as intended and not cause a plug. The front beater, however, can be changed so it won't chew up the straw so badly and damage as much grain. There are different wear paddles from JD you can get now, but prior to that we fabbed our own on one or two machines, essentially making a smooth wear bar that is somewhat rounded off. The straw was decent, but not the best I've ever seen come out of a rotary. Course, some slightly damp straw will come out better than very dry straw. Good luck.