I have bought 2 2wd cossies in the past.Piston slap is common so listen to the engine when its started from cold,if it sounds rattly after a few seconds then goes quieter when warm it will not be far off a re build.You should definitely have a good poke around at the bottom of the passenger side chassis leg(where it comes down to a curve).The water pools in there and cannot get out causing rust from the inside.Also rear arches and door bottoms.Front bumpers can come away on the side mounts so if its down on the sides where it meets the wings then the metal mounts will probably need welding up.Always do a hpi check! A good 2wd with 80,ooo on the clock should be around the 4ooo pound mark.If you need to know anything else then let me know and ill do my best to help you.