Complex sentence: Externally, this model differs due the rear apron of its central body, which is now more rounded, the function of this feature is to make more space to accommodate the catalytic converter within the engine compartment.
Split into simpler sentences: Externally, this model differs due the rear apron of its central body, which is now more rounded. The function of this feature is to allow more space in accommodating the new catalytic converter within the engine compartment.