My very first e46 M3 was a 2002, purchased from a BMW dealer with appeox 25,000 KM. I made sure to find out the history and made sure it was certified by BMW. Also, reviewed all the inspection service reports.
The car run well for me ... 2004 to 2010 when I sold her in all that time all I did was normal maintenance, new set of tires, one brake job and replaced one spring.
The new owner (I am in touch with him) replaced the other rear spring and the car now is approaching 100,000 KM.
Botom line do your research ... here and also use Google ... if it is a private sale have the car inspected at BMW they will furnish you with a report that will aid you in final selling price negotiations.