They all work, CRC, Exotek, etc. just the spacing required to get the correct width / axle spacing from the rear axle bearing to the outer edge of the hub will vary. As long as you have available, or order a variety of rear axle shims, especially 1.0, 0.5, and 0.25mm shims, you will be good, and as stated above, some may be a little wider.

I'm running the Exotek rear hubs with the CRC rear axle on my eXcelerate F1. If I still owned an XRAY X1 and needed to replace the axle and/or hubs, I would not replace the axle or hubs with XRAY parts. An XRAY replacement solid axle is $103, left hub $48, for $151 total, while you can buy a CRC axle and two Exotek hubs for $70.