; Mercedes Sprinter (W906) NCV3 Original radio options - InCarTec

There are multiple original radio options in the Mercedes Sprinter (W906) NCV3, which option is the original fitted system?

Enclosed Subwoofers/ Drivers Enclosed Subwoofers/ Drivers
Extra Slim Subwoofers Extra Slim Subwoofers
Spare Wheel Subwoofers Spare Wheel Subwoofers
Underseat Subwoofers Underseat Subwoofers