Not to take the wind out of anyones sails but in my experience most people do not know what an M3 is and see it as another BMW in a sea of BMWs. The same could be said about AMG Mercedes vs a "regular: Mercedes.
Changing the front and rear bumpers, adding a dome to the hood and putting on different rims does not make the care look significantly different to most people. To be perfectly honest sometimes I have to look twice myself to see if it is an M or a regular 3 and I know what the visual cues are.
But to get back on topic I do not know any M3 owners who regret buying it.
Drivers Club at Lime Rock - International Motorsports Research Center
Madison Avenue Sports Car Driving and Chowder Society (Only a Vice President)
Polish Racing Drivers of America (PRDA)
The Glen Club - Sports Car Club of America