Roger makes two (at least) sizes of rails for the X. One is twelve inches wide, from the frame, and the other is thirteen. He also makes them in two different weight materials. One is heavier for the more hard core user...or absent minded rock crawler.
I'm presently begging him to finish mine before this weekend where I know if I don't have them something baaaad will certainly happen. At least I'll have him to blame for remodeled sheetmetal...
Rock on!