I bought a 135i coupe last year, manual with M Sport package only. M Sport, by the way, was totally worth the $1,300 it cost back then given all the M touches, better seats, wheels, and appearance package. The total before taxes was right around $43K. I use it as my daily driver and it has a fair degree of practicality to it, unlike the 370Z. (and contrary to popular belief, the backseats are usable)
Yeah, the 'vert costs more, and the options can get pretty ridiculous. I saw a fully spec'd coupe at the dealership that came in around $58K, which I thought was insane. But really, most option packages are "don't needs". I don't need the crappy nav system when I got Google Maps on my phone. I don't need the high-end stereo. I don't even like real leather.
Fact is, you can still get a 135i for a reasonable price if you keep options down to the bare minimum. After all, it's not like they make the car go faster...