91-93 were high port intake manifolds. which means that the manifold is shorter and you'll be able to notice it because the injectors are easily accessable. the high port motors had a beefier intake cam that adds about 5hp. these motors were OBDI
94-96 were low port intake manifolds. which means that the manifold was longer and kinda wraped around the injectors. its kinda confusing cuz they called it the low port but the mani was actually higher up then the high ports. with these motors they switched to a less beefier intake cam but they were able to gain the hp back with the new mani fold design. these motors were OBDII
00+ were roller rocker motors w/ obdII but for some reason Jwt cant crack the code on these ecus yet therefore they are untuneable.
so if youre thinking about getting this 93 g20 then get the high port motor or just drop a sr20det in it
or you could just turbo your stock de motor like i did.