1) Pirelli Diablo 140/70-16 rear and 110/70-16 front
2) No.
3) Clutch lever always touches the grip when you pull it all the way. Though if your levers don't match, someone swapped one or the other cause they should look identical (though mirrored). If shifting is abnormally loud or clunky, you may need to do a shift pawl adjustment, just follow the service manual instructions.
4) Get a Jardine exhaust system. When the packing in the can blows out, keep the header and replace the can with a SuperTrapp 4". That's the best off-the-shelf exhaust available.
5) Anywhere you can find them.
6) Oil leaks from the rockerbox, torn front isolator, torn boot, oil consumption (only check oil level when warm), re-adjust primary chain (when warm, loosen tension bolt until you hear clacking, tighten back by hand until there is barely no clacking, tighten lock nut)