I use to have a 93 explorer with a 5spd and i put in a KKM intake which didnt seem to do much other then make her a little bit louder. I put a 40 series flowmaster cat back exhaust system on and that just made her louder as well. I want it to sound tougher so thats why i did those mods. To tell you the truth it really didnt seem to add much as far as power goes. But the sound was good. As far as a tuner or performance chip goes i looked into them and the conclusion i came to was it wasn't worth it because there just aren't enough variables to tune on the gen I explorer. I also put a KKB throttle body on her and that didnt seem to make any difference as well. If you want it to sound better i would just switch out the muffler and save your money instead of buying a catback system unless you want duals or something.
If it was newer i would recommend a tuner for sure. When i had my 1997 f150 i ran a performance tune with 93 octane fuel and that really seemed to wake her up.
