I have a 2000 M5 that I have not started in 18 months and I need to start it again. Can I just drop a new batterie in and turn it over or should I tow to a shop for some reason?
I don't think you want to just start it. All the oil would have run down into the pan. So there will be very little protection during the first period of start up. This could last 10s of seconds and can do damage. So you will want to get oil to the top of the motor before starting. This really means removing the valve covers and pouring some oil there and even removing the spark plugs and putting some oil in the cylinder themselves. I would suggest emailing Mike Miller of Tech Talk about this. He is full of knowledge and will send you down the right path of getting this car on the road. This car has a very expensive motor and I don't think you want to mess around screwing it up.
Sorry, should have given that to you. Email him at techtalk@roundel.org, be sure to include your full name, city, and state. He will want year, miles, model, & transmission type, although on your car it is a given. This info is also in the tech talk section of Roundel. Good luck, Grant