The heads on a 91-96 have the casting number of 7120. They are by far the best flowing heads to get. It will give you big increases in HP/Torque. When swapping to the newer head you have to replace EVERYTHING from the head up. TV cable, intake manifold, exhaust manifold, throttle cable.. everything!
The only thing that you wont be swapping is sensors. Re-use your RENIX sensors. The TPS needs modifications, or an adapter to mate up to the HO throttle body, but other then that its basically just swapping everything out and over. This scenario is the only way to find aftermarket bolt on upgrades.
They do make a exhaust manifold "header" for the RENIX (which you have) buts its a huge waste of money unless you have had head work done. Even then, its still a pretty big waste since the head is the most restrictive of them all.