Knowing BMW, the i is for Injection (sport), t is for Touring, the other i would be ? ... iDrive?
Well, the 2002 tii was made from 1972 to 1974. It was the regular 2 door sedan with the 1990cc 4 cyl engine, with Kugelfischer fuel injection (regular 2002s were carbed). There were also some tii's in Canada in the 2002 Hatchback body style but these are rare today. The tii would do 0-60 in 9.8secs, with a top end of 118MPH. The thing only weighed 2225# and had 130hp/130lbft.
Previous to the tii, there was the "ti" in 2002 form. Can't recall it, but think it was not injected.
EDIT - the "tii" stands for "touring, international, injected". I think (?) the previous "ti" model was for "touring, international" but wasn't injected. Thus the second "i" was added once the Kugelfischer injection was added. I can find no references to the 2002ti, but lots of links to the 2002tii. I know the ti existed because a friend of mine in the Calgary Sports Car Club had one in 1971.