Well, even if you gut it, it will still hurt flow Black because of the chamber expanding so much larger than the rest. Remove it completely and replace it with the appropriate sized PCV tube. It will cost a few bucks from Home Depot etc. They even sell rubber plunbing connectors and reducers if you need. This will provide a smooth straight flow path. I will post a pic later.
Don't go too large on the exhaust. 2-2.25 inch max unless you are going Turbo. A large pipe will kill backpressure and bottom end torque. The factory pipe is like 1.5". Eliminating the cat will add a huge amount of flow by itself.
The Flow is a good muffler as is the Flowtech Terminator (on our car) or if you want more sound, take Black's suggestion.
Also, the Ranger exhaust manifold I mentioned is a factory tube steel header.
MASS air came in 91 and later cars. It is only "necessary" to convert to it if your car is heavily modded but it is supposed to be worth 17 hp and a lot of guys say the 2.3 really responds to mass air conversion.
The bad thing about it is that I have not found one that has a distributor so you may have to take the DIS and pull your distributor at the same time. I have recently obtaind everything except the DIS and will try the conversion soon.