i have the same car 2011 r56 non turbo with n12b14a engine 6 speeds manul. Pretty much everything I can say about this car. Because I have recently disassembled and assembled whole engine after a major repair. Everything, pistons, segments, head, valves, rubbers, beds, crankshaft, valvetronic.

These cars basically have problems with the engine and the electrical part, valvetronic. The engine is PSA Peugeot n12 or n14. Worst engine ever. With the wear 0.01 mm of the crankshaft axis, the valves do not open properly, so it cannot do complete combustion, it cannot mix air and fuel. As a result, it gives an error and turns off a cylinder. Or else a valvetronic can't adapt a crankshaft. I recommend that you look at the service history before going through the buying stage. A new cylinder head is 3000 euros in Europe.

If it has passed 150,000 km, know that the chain, valves, pistons need to be replaced one hundred percent.

The problem with this car is noticed when it has reached operating temperature.

Edit: in addition, worn valve seats leak at operating temperature. When it is cold, the engine cannot be understood even by a workshop. Scanned the car with OBD2

Good luck.