to be a truly motarded your first step would be to sell the xr and buy a motocross bike. plain and simple.....
however if your just looking for fun then yeah set of wheels and tires and your good to go, but if you looking to go track riding then good luck. to be honest, no motorcycle is further away from being competitive in its respected class than a dirtbike in a motard class. real motard bikes have stiffer/completly redone suspension, 17 inch wheels front and rear, with a wider rear wheel to allow 150/60 motard tires, a new front brake/mount/rotor/master cyclinder and so on and so forth. as I said nothing is further away from being competitive, buy a gsxr 600 and your 700 buck away from being competitive, buy a motocrosser for motocross and your 300 bucks away from being competive, buy a motocrosser for supermoto and your normally 2000 bucks away from being competive (yes there are exceptions, but you get my point). And in your case, your a new motorcycle and 2000 bucks away from being competitive. that being said it looks like a blast and as stone cold reliable as the XR's are you will probably have a blast for many years to come with just a set of sticky 17 inch tires.
