I have DSE upper control arms and SpeedTech lower control arms (I did mine so long ago DSE's LCAs were still in development). I don't recall if my STs have steering stops. I think they come that way now, but not way back when I bought them. Don't think they have added built in caster either like DSE's.

The delrin bushings are are virtually friction-free, so if anything they improved the ride. I even went up in spring rate and sway bar size at the same time and it felt smoother (same shocks before and after swapping the arms).