- Maintenance is pretty much the same as any car its age. Regular oil changes, i do mine every 5000km but you could get away with 8000km or even 10000km if you use fully synthetic, which you should. Regular servicing, timing belt and water pump change at 100,000km intervals etc. All standard stuff.
- Fuel economy all depends on how and where you drive. Highway you will see in excess of 400km to a tank but around the city expect 300km per tank. You must use 98 octane and only resort to premium or regular unleaded if you are desperate.
- Any car audio place will have fitted 250000000 skylines before so no dramas.
- There is no factory alarm in an R33 really. Some had factory remote entry but not many. Many examples for sale in dealers will have aftermarket alarms.
- Parts are readily available but slightly more expensive than say holden parts, but theyre coming down in price. You have many options nowdays though with so many import wreckers. Nissan will also get new parts in for you.