There is a brake upgrade for pre-95 models that require changing to 95-97 I-beams. So unless you want to downgrade your brakes stick with 95-97 I-beams.
Edit: Now that I think about it, I believe the I-beams are the same, it is the spindles that are different.
I have never seen a Ranger that came with different sized tires. Someone probably put them on that way.
I went a different way than most with my four cylinder Ranger. I put 15x8 rims with 255/60R15's all the way around. No rubbing. Looks tough, handles amazing. I did have to change speedo gear...
The cam is a major factor as to how high your motor can rev. If you put a high RPM range cam in it then it will rev past 4K.
You can have the PCM reflashed or you can buy a chip that will plug directly into the PCM box. (EEC)
Upgrading coil packs, plugs, and wires will help if your old ones are worn. You already have a cold air intake if it is factory. Premium fuel is for when your engine is pinging, it is not a power adder unless you have the ability to advance your timing. (Or is it reetard, I forget which way it...