Planning on buying a 97 Warrior this weekend which is still stock. Looking for input on what to add on from the start?

 

In the interest of extending the life of your engine, not to mention better breathing & performance, I'd suggest dumping the stock air filter & replacing it with a Pro Design air box adapter & filter, giving you a positive seal to the carburetor intake. Then you could get some decent tires which will not roll over in hard riding and hook up to get your power to the ground. After that, A better pipe/silencer combo will give better performance thruout the band. As you gain experience with your ride , you'll no doubt want to upgrade your suspension to meet your increased skill. After those improvements, the list becomes a matter of "how fast can you afford to go?". Along the way there are a multitude of accessories you can use, such as steering dampers, twist throttles, alloy handlebars, & on and on. Also, in modifying your air intake re-jetting will be necessary.
In case the foregoing appears to be belittling your bike, they are all things I've done to my 97 Warrior to make it more fun to ride.
Get the wallet or credit card out & have at it!