We too had an ST 4000. Started getting error codes and it also started to drop the course. Was advised that the fix might be more the cost of a new one. So we went with the EV system. It perfectly dovetails with our e7 chart plotter . Couldn't be happier.. Go for IT. !!!I have a 1979 S2 9.2C. The Ray Marine Autohelm ST4000+ not working anymore. I am thinking to replace it with the Ray Marine EV 100 system and install it instead. I read good reviews about it. Is any member of the forum think against it