I have a 88 rx7 with pretty much stock suspension. I did have to put a aftermarket front swaybar on the car. When I installed it, I made sure it was centered and the endlinks were at just about the same angle. After driving 200 miles or so I checked on the bar, and it had moved over toward the drivers side so the endlinks are not at the same angle. Is this normal for it to move back and forth like this?

 

I don't know about the FC but you could install some collars or spacers to avoid the bar sliding.
Go to www.mcmaster.com and look for "shaft collar". You should be able to find something that would fit. The double extra wide collars work best.