I was just giving him trouble
Read above, and you forgot rims, spoiler, quad exhaust, interior trim and SMG trans.
My friends all thought I had an M3 for like the first year I had it... it was only in chemistry class one day did a couple of them figure it out. Most people will not notice larger brake size, fender size, or the presence of an LSD without some assistance.
And there are differences between a 323Ci and a 330Ci (especially ZHP), such as:
front and rear suspension components
front and rear brakes
LED/HID adaptive lights
Engine (m52 vs cammed M54)
5 speed / 6 speed
To us (enthusiasts) its a very quick thing to pick out, but to most people a nice black bmw is just a nice black bmw.
I have picked out a M3 from over 2 blocks away before, and Im not even kidding. (it was black, the fenders gave it away) It was only once we had caught up with it were we able to confirm it was an ///M lol