crossmember and both sills! get on ya back n check it thoughly, how old are the cars? if there a few years old like 7,8,9+ give em a hard "tap", sill replacement and crossmember replacement is pricey (unless you can weld) and its a right faff! erm.......3 door, as with most cars, doors tend to drop (dunno id that bothers you tho!) errr........smoke (bad light blue means sumic but i cant rember what, im sure)and check for crash damage, micra's are so easy to do imo, and some people buy them from scrappies (write offs) and fix em all up so check under bonnet, check the engine bay, where the wings are bolted on, check that, check boot floor etc. thats all i can think of, others will let you know more tho!