I'm 55 and drive my M5 quite hard! I also have a heart condition!! Condition, history, history, history all important. The M5 is built to be driven so don't worry about how they are driven. The ones with good service history should be ok. I personally use an Independant because the local BMW dealer charges stupid prices and like most franchised garages use cheap labour. You just get charged for the privilege. My Independant looks at CBS and preventative servicing. At 30 k miles all fluids were changed on my beast.
