The 2013 335i supposedly has a newer DME, and every time they change the DME, there's a whole new set of code to be deciphered. BMW started making it harder to do flash tunes in 2010, and it takes time to get past the encryption and so forth. I'm ordering a new F30 M-Sport Line and figure they'll have something for it by the time it's delivered in early March. Right now, the M-Performance PPK looks like a good bet, although I'm hearing that it includes a new engine cover and some other non-tune-related stuff, making it pricier than it should be. Meantime, I'm hoping to get the car ordered with the M-Performance exhaust and black grilles so I don't have to fiddle with installing them after delivery.
2013 F30 335i M-Sport 8AT/MPE/MPPK, 2016 228i M-Sport Cabrio 8AT