I found that it was best to go ahead and get the Volvo Tech manuals on this car. I had bought the Chiltons and found it to be very limited in help. The electrical one is the first I would get followed by the fuel injection.

There is nothing wrong with the WIX filter(IMHO). This car needs to use syn fluids to keep it at is best.

I hope you have the service records for this car. If not then the timing belt is the most urgent need. Please read the FAQ on this car as it has alot of good information.

Coolant is important and this includes hoses. Loss of coolant is diastrous for this engine. About as bad as a broken timing belt.

If you plan on changing the timing belt(every 30K) then consider the water pump and the tension assembly unless you have proof otherwise that these have been changed. The manual on this is pretty clear with lots of illustrations.

If the only way to change the light bulbs is to take out the dash then get the manual that covers where are the screws are. Take my word for it that the screws are not easily found.