Ok apparently the 135i unit and the F30 335i are the same: code 11 35 2306 J.
Here is the 135i: http://www.hartge.de/e/bmw_motor_4915.html
Here is the F30: http://www.hartge.de/e/bmw_motor_6577.html
--> Same code.
It kind of makes sense since both are N55 engines but I have no idea if the F30 has exactly the same or an evolution of it. On the tunermotorsport website they only say it fits the F30 335, the F10 535 and the F25 X3
No mention of our 135i...
I've sent an email to both Hartge and tunermotorsport for confirmation.