bg_saber.c and w_saber.c will be your best bet. Most of the stuff I've changed in the past has been in w_saber.c though, but its best that razor tells you where to start since he's the true sabersystem guru.
While the MB2 saber system is good (and originally based on some of our really old code with a ton of their own modifications for the way it is now), with our OJP Enhanced project, we've been trying to create an even more movie realistic and close quarter saber system then MB2. If you haven't tried it yet, I highly recommend it. I'm a big fan of MB2s system, but I left it to work on this one.
And if you want to ever help with further coding for Enhanced, Razor may very well be retiring soo and we might need another good coder who likes altered saber systems. We also wouldnt mind some work on seige and have even been debatingn whether or not we want classes for it, but our future isn't certain after our next public release.
Game screen name: Master Jon Hoc Ni
UDM Quote: in singapore, gangsters are...skinny jacka**es who think they can 0wn you. they hurl insults at u, and then lose in a fight. n00bs