I just opted for M5's on the ZRX this time and went for my first ride on them this morning. I ran 35/38 cold pressures, as the temperature was cool when we started out but I knew the day and the road would warm up considerably by the time we got home.
First impressions are very pleasing. As my confidence in them increased, I pushed things harder and they didn't budge, even when I got a bit ham fisted with the throttle. Rather than spinning up the rear, it just squatted more and accelerated hard out of corners leaving me with a big stupid grin on my face.

The front feels solid, tips in nicely and changes dirrection well. I think M5's are a great choice for big heavy bikes.