i have sierra fitment shocks in the rear of my car. they are kyb excel G's. i am running a pair of trd 6kg springs, which have been cut down (which increases their rate).
the suzuki shocks control these sprinsg okish. definately a little bouncy. theyre also extremely short. shorter even that a tockiko HTS 102 (the shortest rear shock that manufactuerer makes for the ae86).
i think there are definately more suitable OE shocks out there. i got mine brand new as part of a trade, the car theyre in is a throw together so im not complaining.
you can use the munroe catalogue to cross referance sizes and fitments online. something from a slightly heavier 4wd might be a little better. maybe triton? also consider looking at stuff from vans, which are often pretty short.
the front is more important. spend some proper money on some ajustable inserts. MR2 fitment (from the front or rear) is a good place to start.