The EJ22s can be broken up into several blocks of year ranges.

Phase I engines
90-91 - the engine plugs come out near the left timing cover, just above the
cam sensor.  They have three engine plugs.  The injector plugs are angled at
45 degrees relative to the intake runners.
92-94 - the engine plugs also come out near the left timing cover, but now
there are only two plugs.  The injector plugs come out straight relative to
the intake runners.
95-96 - the engine plugs come out over the bell housing now, one grey and
one brown plug, from now on.  95 models start OBD-II, with the OBD-I plug
still present.  Mid-year 1996, some engines began to have single port
exhaust (previously dual port), and this continued for the rest of the EJ22
series.  1996 MY engines could have single port or dual port exhaust, just
to be clear.  Up through 1996, all EJ22 engines were completely
non-interference.
97-98 - EJ22 engines are now slightly interference with a slightly changed
piston.  These engines got a new coil pack, a molded plastic unit now set
slightly off-center on the manifold and held with only 3 bolts instead of 4.

Phase II engines
These engines have little to do with the earlier engines, but are still
designated EJ22.  These engines have tall squarish valve covers with the
head bolts now under the cover instead of exposed.  Early ones still had air
flow meters but that disappeared in 1999 in favor of a MAP sensor.   None of
the phase II engines had ignitors.

-Hans
http://www.vanaru.com