I can turn up spacers if you do need them in the end (as can utopia and a few others on here)
s2r 800 uses 300mm discs not 320mm, so the offset is the least of your worries. The quickest answer for the calipers is probably something like these
https://www.performanceparts.de/en/A...m-caliper.html
...doh! you need 65to40mm adaptors, not the other way round, so perhaps these
https://mcet.de/eshop/en/en-spare-pa...rs-65-mm-40-mm