Okay, I feel pretty stupid even posting this but here it goes. I consider myself a fairly competent DIYer. I've been doing my own work almost as long as I've been driving. All my previous experience however has been on domestic vehicles, this is my first BMW. I am working through the inspection list at 100,000 miles. As this is the recommended mileage for spark plugs I began the process and almost instantly second guessed my choice. After removing all covers, coil, etc. for the first plug I grabbed my plug wrench and began to turn. Here is where the questions arise, the torque spec is 18 lb/ft. When I began to loosen the plug it seemed much tighter than I expected, and after about a half turn felt as though it was still snug, at this point I resnugged the plug and stopped. It felt as though the threads were galded/damaged. This is my first experience with an aluminium head as well, is this normal? I am concerened about removing the threads from the head with the plug and ruining the head. Has anyone else experienced this? Should I start with a warm engine and try again? Should I leave this to a dealer and just pay the high price and let them have the responsibility of dealing with it? I hate to pay anyone to work on my vehicles but I would hate replacing a head worse. Any suggestions?