I recently drove a 2013 Sport Line 335i with the 8-speed trans, and while the steering felt different, it also had several "modes" to choose from. Sport and Sport Plus were the best settings; the 8-speed in Sport mode held the gears when accelerating - decelerating - accelerating. Auto start/stop can be programmed to be OFF as default, so that's not a problem. I don't like the i-Drive display location - looks like it ought to retract or something like that, but it's not movable. Aside from that, the M-Sport Line adds all the aero stuff, M Steering wheel (really nice!) and a few other items.
As I'm looking for something a little bigger than my E92 but don't want a 5-series, and I've decided to go back to a sedan, I've ordered a 2013 M-Sport 335i. It's different than my 07 E92, but it's the right car for what I want now. It'll take a few months to get it delivered, but I'll have first-hand experience to report after then.
2013 F30 335i M-Sport 8AT/MPE/MPPK, 2011 128i M-sport Cabrio 6MT/PE