structural rust rust and more rust, and there might be rust you can't see too

if you don't find any rust check for noisey engine leaks and bodged repairs.

if you find none of the above make sure all the lights and electrics work and the VIN numbers are correct.

and don't get caught up in how fast it feels because your better off buying a slow good one and doing the work yourself.

and HPI it

then you might get a good one.