...definitely worth it! Its exactly what the dealers use to locate the parts you need. It strips the car right down, even to every single nut and bolt holding the car together. Gives you exploded, detailed diagrams. You just click on the sections. Gives you all the part numbers as well, so you can go into your dealer and say 'I want part number X'. Its definitely a good tool to have if you're trying to find what could be causing a particular problem i.e. you can see where the oils coming from, but what needs replacing - well this tells you!
Shame its only the parts CD's which are supplied and not the other sections which are listed on the main menu i.e. Accessories, Repair Procedures etc.
Good stuff!