Yes they have a mesh filter for the big stuff (you should also run a magnetic drain plug) and the oil slinger picks up the rest. They are a very effective filter and have been used by hondas for years.
umm i dunno i think the same job but just lighter.. but if your lightin the slinger then you need to get a new inner rota kit to even out the weight differnce
these engines do not run an oil filter, the oil slinger takes in the oil, spins it, and pushes the junk to the sides of the oil slinger (needs to be cleaned out every few months or so), this is the "oil filter" setup on these engines.
because it is on the crank, a lighter one would mean less mass, and therefore will spin up faster, and rev faster...in the same way a lightened flywheel or inner rotor works
So well now i have another question if it required to put a new IRK in for a new lightened oil slinger then does it mean that if you were to a new IRK regardless would you still have to replace the oil slinger