yea if i were you depending on your budget get an HMF slip-on and a DynoJet jetkit...these are both on Ebay, pipe is like 247 and jet kit is like 30-40, and get a k&n filter or pro-flo or twin air and take the airbox lid off that should get you started
I have been looking to work on my 89 but it seems the warrior has become obsolete to the new machines, the engine sizes have doubled in the past few years and the technology has killed making power in these bikes. You can do the filter, pipe, drilled airbox, and some jets. You can always change your sprocket sizes to get more top end or lower it for torque. Mike