if you look in the MT section ( http://forums.2gnt.com/dcboard.php?az=show_topics&forum=34 ) you should be able to find a bunch of info. but basically a modular clutch has the flywheel rivited to the pressure plate and uses a flex plate. a non modular has no flexplate, and the pressure plate/disc/flywheel are all seperate.

dsm/mitsubishi service manuals https://www.mediafire.com/folder/5k14qlaulb9s1/dsm_mitsubishi

service manuals(my whole collection) https://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals