Perfect fit but need more screws.
Since my bike came equipped with 180 discs and Magura QM40 (the 160 to 180 adapter), this QM42 is the adapter I needed to make it 203.
Unfortunately there is only two short screws included, and I need four short screws to mount it. Two screws to mount the caliper to the adapter, and two more to mount the adapter to the frame. Lucky for me I bought two of these so I can mount one of them. The screws already on my bike are far too long to use since they're designed to fit through both the adapter and the caliper. If your bike has 160 discs it probably has the correct screws to use. Wonder if I can cannibalize some 160 Shimano screws....
Anyway the 180 to 203 upgrade seems well worth it when you're having fun on a heavy E-MTB and not chasing grams. 203 mm SM-RT76 looks amazing!