Petrol variant, some had twin spark plugs per cylinder, if coil packs and leads are bought from mercedes they are crazy money. The aluminium inlet manifold version is better as the latter plastic ones have the swirl flaps which can be prone to caking up and seizing. The diesel ones tend to get leaky injector seats, easy to see pop the engine covers off (torx bits) and there will be mess round the injector, not difficult to sort.
Don’t always discount mercedes for your parts as the other day they were cheaper than any other motor factor for discs and pads and had them on the shelf when all around hadn’t.
Regular servicing in the main seems them to running to a good age, mot wise, front lower wishbone bushes are starting to pop up regularly.