The main external difference is the presence of the small winglets on the tip of the -200's wings. As a result, cruise performance is more efficient and the -200 has more range. I'm not sure, but the -200 may be equipped with uprated engines and other internal differences, but the fuselage is identical.There were not many -100s built. BCAL ordered a few and they went to British Airways in the coat-of-arms scheme and you might see one in the photo section of this site. Of course, BA has new 200s on order but these are much newer, by ten years.