My new model! a 1959 Porsche 356 Speedster
It has nearly 2000 pieces and is also a B model from the 42056 Porsche set from 2016.
It was a very challenging model because of the curves that it has, like the bonnet that is very similar or the same from the Volkswagen type 1 has and the trunk that is the same from the nowadays Porsche, but those angles were not impossible.

The functions are:
.-RWD, with a differential
.-A sequential gearbox with 4 speeds
.-A Boxer engine with 6 pistons
.-Steering with working steering wheel
.-Suspension on the 4 wheels
.-The 2 doors, the trunk, and the bonnet can be opened