hi, i live in oz via uk and happily owned a AX 1.4D which i did basic oil and service change. i now have a C4 coming upto 40,000 km service at a silly price over 300 quid which includes oil and filter, fuel filter, pollen filter, spark plugs and air filter. i would like to check if these need replacing but don't know where to start under the bonnet - any help - please. andy ps is all this replacement necessary anyway???????