Interesting on my s4r the caliper is undeslung like my 748s i had, so guess i have the same caliper as the 748. The s4r works better than the 748 but not much more. This may be due to the master cylinder being at 45 degrees.
I also found my 748 and s4r brakes from new worked once u bed them in slowly and use them regularly. The disc on the s4r looks to be bigger to hhhhmmm
