1990 is still a b12. it's fuel injected, but the GA16i is single point throttle body injected. it has ONE injector going to the throttle body.
It's extremely limiting. i'm in the process of doing a MPFI conversion using the GA16DE intake manifold, throttle body, and ECU. if this works, it'll provide a much stronger, and possibly more powerful base engine for boosting at less of a cost but with a bit more time put in, than swapping in a GA16DE and boosting it.