It will work, but you might not get to use a dedicated magura rotor. For mine, I am gonna use a Hope one.
Logical thinkin here.
If you are supposed to use a mount for brakes that are 160 calipers, but using a 203 rotor, then it seems to me you have 43mm to play with. So, no magura 210 rotor. But you should be able to use a Hope or Hayes rotor just fine. I've run, and will be running, my Gustav's on a Hope rotor and it works just peachy.
not exactly sure, but I don't think that Magura makes a 160mm adaptor for the Gustav's. I was running some Louise FRs on the 40 for a bit, was running a 6" adaptor with an 8" hayes rotor. However, not sure if that setup would work with the Gustav's, as they may have a different mounting bracket?
Thats not true man. Post mount is the non-standard. IS (hence the name, international standard) was supposed to be the standard, but hayes had to be difficult. Now its not so bad, as companies like Avid have proven thier mountain system to be better.
Anyways, i still think that if you bolt the 160 Gustav Caliper (which i have here) to the Fox, and run a 203mm rotor, you should be just fine. I will try it later, if I can be bothered.