More stuff:
Aftermarket fork springs are a good idea esp. on the Dakar where I'd call them essential. Once you have them you don't want to be without them any more. On the F650GS aftermarket fork springs are more an added comfort issue but are still very worthwhile.
If the fork oil seals leak check very carefully for rust pits in the inner fork tubes. If the tubes are pitted your repair cost easily doubles to R3,000 for grinding & rechroming the tubes and all disassembly and assembly work. Protective fork boots are essential even if you only do dirt occasionally. Opinions are divided as for the benefits of neoprene seal savers and rubber concertinas. Decide for yourself which ones to fit but do fit either the one or the other.
The OEM brake lines aren't very nice quality. The nylon / rubber hoses of the early models are best replaced preventively with stainless steel braided aftermarket stuff which lasts longer, looks better and costs less than OEM (Note that the OEM brake lines are scheduled for replacement every 4 years)
The nylon liners eventually tear and the brake hose blows up with your brake basically not working any more. Occurs from one moment to the next and without warning.

Remove the radiator louvres and check for repairs on the radiator behind the frame downtube. Stones end up in there and vibrate holes into the radiator. If the radiator was fixed with epoxi this is a good reason for a few thousand Rands discount as there is no guarantee for how long these epoxi repairs last.
Once the bike is yours take the louvers off and check for stones after every day on the dirt.
A maintenance free battery is a huge plus. Forget all that was said about leaking battery acid. Yes they cost more than a flooded cell battery but they last longer and- require no maintenance. And their self discharge is lower too means you can save the money for a maintenance charger.
Worn or rusted swingarm pivot bearings and suspension link bearings give themselves away by making creaking / squeaking noises when you bounce the bikes tail.
Check if there is rotational play between the rear sprocket and the wheel. The cush drive dampers wear out more or less readily dependng on the riding style. This results in sticky and noisy gear changes, increased wear of the chain and sprockets and various other parts of the drive train.
Replacements are over R 800 for OEM, slightly less for more wear resistant generic polyurethane dampers.
(edited on 03-02-2013:) IMHO the wear of the OEM cush drive dampers is more due to riding style than to batch quality of the parts (?)
Check if the rear shock hydraulic preload adjuster works. Stripped adjuster knobs are common, blown hydraulics can be seen too.