1. it should tell you in the haynes what to change, just loan one from your local library for nowt 
2. It has a timing change and is meant to be changed every 100k but tbh very VERY few changes snap, and its probably due to being hammered.
3. unknown about PAS, was probs an option like most models, check your tyre pressures.
4. Change the box oil, this could help greatly
