These are Disco 2 under a series 1 width body. A standard defender spat don't cover the standard wheel with a 205 diamond. As for strength Drew Bowler used them under Wildcats on the Dakar with standard shafts and never broke a CV. then again uprated CV's and shafts are available
having said that is it worth the trouble changing axles why not just up rate the standard ones, most challenge trucks do OK on them, I fitted D2 to save weight for a race application.