The 95 manifolds are better. If you are changing everything then why not get the better passenger side manifold? Driver side is still the same. Porting the outlet is not a big deal, but again, why not when you have it apart? If you want a pair of ported 95 manifolds with new studs installed, I can probably work that out, I think I have some spares laying around.
The rest of the exhaust is not that critical believe it or not. The stock cats are not that bad (we have made over 300rwhp many times with stock cats). If you replace them, I recommend a highflow version, but not a spun metallic core if you have any interest in them actually working as a catalyst and/or sound deadener. I've posted the part #'s for reasonably priced cats many times on here, search is your friend.
If you run cats, then the rest of the system is not so critical, sound wise, but if you eliminate cats then sound will be a major concern. For 300rwhp or less, pipes need not be bigger than 2.25". In fact 2.0" will work fine too as long as they are mandrel bent, and personally I would never use a crush bent piping system.
www.mandrelexhaustsystems.com is hands down the best place to buy exhaust piping. I use their stuff all the time and highly recommend the stainless dual system with resonator. You will have to supply the down tubes though and I highly recommend the late model version as it fits much better than the early model one. You'll need a late model gas tank.
Keep in mind that the bigger the pipes, the louder the sound, and the lower the internal gas velocity. Velocity is your friend at lower rpms and lighter engine loads. If you spend most of your time driving normally, then a smaller exhaust system is superior to a an overly large one and it will be quieter to boot. I can't count how many SC's have been literally ruined with oversize, obnoxious exhaust systems.
I have had GREAT success using the Magnaflow cat/downtubes from Summit or wherever, and then connecting that to the mandrelexhaust system 2.25" rear section. Out back I angle the muffers at 45 deg rather than going straight back so that I can fit 18" mufflers instead of 15's. The extra makes a difference. Or you can go cheap and install a chambered muffer with packing instead of straight through. At the 300rwhp level it won't make a difference either way. I've actually made 350rwhp with this exact exhaust system, but boost was climbing pretty badly so it's not recommended at that level (21psi boost).