I purchased my M3 as a certified pre- owned about 2 years ago. The car is flawless. It can out run or keep up with many cars on the road today, easily. It is very quick, responsive and handles as if it's on rails. You can basically attack corners with this car and never feel over your head. The car also makes you look and feel like a better driver. The functionality of the car is also impressive because you can carry four adults in relative comfort with a few bags of luggage in the back. Most of all the car is fun to drive and will definitely put a smile on your face whenever you drive it.
My favorite features are: the multi mode automatic transmission, mulberry interior, fold down rear seats, the overall interior ergonomics, and the overall solidness of the car. The motor is also a favorite feature, it very reliable with proper maintenance. The exhaust note is amazing.
My suggested improvements are: a more reliable climate control system is needed because it is a common failure item. The taillight bulbs tend to go fast and there may also be a short in the overall assembly and wiring. There is also interior vibration from time to time.