The M3P is now putting down 3.0 sec 0-60mph times now, 11.5 1/4 miles times. The M3P+ has bigger brake rotors, big red calipers, larger brake pads. It also comes with Michelin PS4 performance tires and Track Mode with tuning assistance from Randy Pobst. The suspension is lowered about 1/2 inch and you get a carbon fiber trunk lid spoiler. And don't forget the $30 silver pedal covers and badge with a red line under it.
Ideally, the performance model would have included some other performance related items to help differentiate it a bit more such as sportier seats and mag ride suspension but it is still a bargain for the performance you get when compared to similar ICE based sports sedans.