Where to purchase: Amazon.com Price: $85.00

Bentley's BMW 3 Series (E46) Service Manual has been the single most important resource for me in servicing my vehicle. It's pretty expensive at $85 but it pretty much pays for itself with the money you save by servicing the car yourself.

The Bentley manual has detailed procedures for just about everything you would ever need for your E46. This includes procedures for everything from changing your oil to swapping out your differential. Want to know how to replace your driveshaft with a new one? It's in there.

Some of the most important pieces of information you need when working on any vehicle are torque specifications. Even if some procedures seem elementary to you, you will still need to know how tight to torque all the bolts when you're finished. Needless to say, the Bentley manual gives the correct torque specifications for every bolt you would ever need to fasten.

One thing that I need to mention is that while the Bentley manual is an excellent resource for working on your car, it's not perfect. I found it particularly frustrating that while many of the procedures in the book call for raising the car and placing it on jackstands, NO WHERE in the book does it detail exactly how to do this. Where are the jacking points that I can use under the car to jack the car up so that I can place jackstands under the four jackstand points? No mention of this at all.

If you are going to work on your E46 I would highly recommend this book. Besides the issue of raising the car mentioned above, this is a great resource to have when you need a reference manual for your vehicle.