From my understanding, FA does final assembly in the US, but the parts come from Taiwan just like BC and Megan and 147 other companies. The build quality is going to be pretty much the same. What I have read and heard is that FA does a better job with the damping than BC/Megan. Not sure if their design is better or if they just do a better job of selecting the shock to the application. I can see that being the case, I like the BC's on my car, but the shocks aren't really matched to the application and neither are the springs. I don't think they took the weight of the FX into account when designing them. It works, but there is room for improvement.
All of the "cheap" coil over companies pretty much have a handful of shock bodies to work with of different sizes. They then machine the proprietary hardware for each application to make it fit. FA may do a better job at this than BC/Megan, who knows. But I do read a lot of people swapping from BC to FA, I don't see the reverse. They are more money though, so it's not a direct comparison.
