e46 318i is 2.0 for 2002 onwards ( fuel saving, 5 speeds, twincam, can achieve 210km/h if u dare )
for 1.9 e46 318i is 00 and 01 version ( fuel saving but nt as save as 2.0, 4 speeds, single cam, hardly can get 180km/h )
for 1.8 e46 318i is 99 and 00 version ( not so good in this version ) XD
these are the information i got
currently i own an e46 2.0
e46 318i 2.0 is my suggestion, u'll feel shock of the fuel saving
consider about it 
cheers!
