Not quite on topic, as its front brakes but, I've a 05 636, had already tried improving my front brakes by ss lines and using 5.1 DOT brake fluid, no love. Just installed Nissin calipers and used Vesrah pads. The difference is night and day. First of all I have only maybe three quarters of an inch of full travel from total off braking, to full on braking, with amazing progressive bite from almost the moment I touch the brake lever. (when I first put them on I thought I had not put them on right and they were permanently locked on, as there was hardly any travel in the levers) I feel I could flip the bike by using 1 finger. I always had a feeling with the original set up that, especially when braking from high speed, that I wasn't sure how much brake I had left to expect, as there was just so much spongy travel. As a mod, in the top 3 for me.