SpiderTrax is based in Colorado about 15 min from where I used to live.
They are huge in Samurai off-road buggies and into general 4x4's as well. They are a bunch of good guys that will invite you into their shop and right in to sit down in the office and go over what your build goals are and how to accomplish them.
I used their spacers on an old CJ5 I built up because I wanted to swap wheels and tires from my YJ to the CJ. They held up great through normal street driving as well as rock crawling.
Great product from a great company. Didn't know they worked with 4wheelparts. That's probably their only mistake :smiledown:
just want to add, i was told they are illegal in nj. never checked if this was true, but if it is there might be other states where legality might be an issue. really don't know how law enforcement could detect at a road side stop though.