The fastest K10 MA10's i think are those autograss boys they get their 1.0l K10's over the 100bhp for racing :)
http://www.micra.org.uk/threads/37874-Autograss-class-4-2-micra-k10-on-ebay?p=401448&highlight=#post401448
"car weighs 490kg and has more bhp per tonne than a mitsibishi evo 10"...