The '84 cars had a different layout for the intake system. They had 4 runners in a row. This design was not all that great, and allowed no room for creativity, or porting. Anything after '84 switched to the much more efficient "4 square" intake which im sure we are all familiar with. They allow gutting of the upper and knifing the lower to give a shorter intake runner if the driver prefferes high end power rather than low end. The turbo cars use the same basic intake as the N/A cars...
There are a couple different versions of the same "4 square" intake which i have seen in my many trips to the local JY. But, there are no big differences between them. One is a little smoother, and easier to port if you ask me. The other looks better on the outside, with the casting "2.3L EFI."
-Ryan