Ivo
1998 is the around the crossover between short and long door cars. Obviously the long door cars have the stainless bulkhead and inner wing valences , which are preferable , but I would not let that dissuade you if it proves to be a short door.
As others have said the engine is pretty bombproof, the R380 gearbox is not the fastest shifter but again is pretty bomb[proof as it will take the torque of a much more powerful car (Holden Monaro 5.7 V8) , the Dana Spicer rear axle is also from the same stable , so the drive train is the least of your worries.
The chassis will be galvanised , so no rust , but just check that all is straight and true underneath, and that everything looks to be well fastened.
Is it in the original exhaust? If so budget for a new system quickly , as the silencers from this period were very restrictive, and the cast-iron manifolds not much more than a joke. You can release a lot of restriction by going to a "Librands" type system . not cheap but very worthwhile.
I would look for evidence of overheating (an alloy radiator can help cure this ). Try to ensure that all the electrics look good and have not been tampered with.
Other than that it is just the normal things , condition of the paintwork and upholstery , do you like the colours, and just a general "feel" ie: has the car been "loved" during its ownership.
Good luck , and send us some pictures.
