Thanks for all the info regarding changing the plugs on my E430. The 17mm wrench is a MUST HAVE! It makes removing the metal casing on the plug wires TOO EASY! I recommend removing the air filter box assembly to get better access to the plugs on the passenger side, and all the coils on both sides to give yourself ample room. Also a 5.5 inch socket extension will give you enough 'clearance' to get a good turn on the plugs. I also used a 6 inch length of 3/8 inch rubber hose to get the plugs started in the heads (there are some tight corners in that engine bay). From start to finish the job took about 2.5 hours as I dropped the socket, hose, plug, wrench, etc, etc. It was a fun experience changing the 16 puppies out. Also, having the filter assembly and coils removed gave me an opportunity to do a little 'house cleaning on the manifold, heads, etc.