+1
I bought my first one in August 2007. A year and half later, at the outset of the great recession, I found myself jobless with an $812 car payment. So I put her up for sale. Lots of alleged interest, no takers. Then I realized I didn't want to part with it, and paid it off. That's one way to eliminate a nasty car payment! Kept it till 2015, when in a moment of weakness, I let it go in favor of a super-clean E39 M5, something I'd wanted for ages. I never could fall completely in love with the M5, and missed my Z4MC almost immediately.
Fast forward to last November, and I decided it was time to rectify the situation. Found the perfect car and pulled the trigger. Not making that mistake again!
Kids, think LONG and HARD before deciding to sell. These cars are rare and nothing like them is EVER coming back. They are the last of the "analog experience" M cars. The last of the naturally-aspirated M cars. The last cars without iDrive or a buttload of fancy (and unreliable) electronic driving "aids". Hang on tight!