Some things that have come up in previous coilover discussions are warranty, customer service and rebuild facilities. You really want to make sure that the company that makes your coilover has an office in this country.
If you need to call Japan to ask a question or do something under warranty, well...it's an expensive call.
Tein, JIC and Endless/Zeal have offices in the US. Last I heard, JIC wasn't set up yet to do rebuilds in the US, so they ship their stuff to Japan. Tein rebuilds their stuff here. I don't know a hell of a lot about Endless/Zeal but the website makes it sound like they can rebuild non-race stuff in the US.
Anyway, I've never heard of Fightex and I'm not sure about Toda's US presence. The site only lists a North American distributor.