ugh. If you mean mechanics and performance wise they are all basically the same. If your just going to scrutinize over little differences i would say the best year is the 89. Its got all the stuff as the newer ones up to 92 but is still the lighter wieght and older (i like old). The 88 is the next best choice (and is the best choice for a 325e) because though it doesnt have plastic pretty bumpers it still has most of the changed from the older 87 designs like ICS (sensor and not valve) and like he says the fuel pump. Beware though they made 2 models of the 88 pre and post change. One has older 87 components and the other has newer 88-89 components. The easiest way to tell is to look for the large ICValve on the intake boot or the smaller ICSensor.
<span style='font-family:Geneva'><span style='font-size:14pt;line-height:100%'><span style='color:red'>Fox</span></span> <span style='color:gray'>the Pirate</span>
Diplomacy is saying "nice doggy" until you find a rock.</span>
I live my life one quarter mile at a time, and for those 23 or more seconds I'm free.