Having owned both the W124 (E220) and E32 (735i, which is closely related to the E34 build quality wise, except for the the engine) For durability wise, definitely the W124 is the more superior car, as the components of the W124 are more solid and the plastics hold together much better than the BMW's.
Engine wise, if you're looking for a reliable model, I would say the 260E is the engine to go for as, it's more mechanically sound compared to the later muti-valve E220 and E280, as they have those bio degradable engine harnesses, which is super expensive to repair, same goes for the throttle body wire which is wrapped in the same material.
Spares for the 124 can be sourced easily as well since, they still have support for 3rd party parts shop, around KL and PJ. If you need a specific part, halfcuts can be sourced easily from Hong Kong or Japan. BMW is a little harder unless you're talking about the 3 series.
Driving wise the W124 is a big old school cruiser, whereas the BMW's driving dynamics is just a class above it, in every area. Comfort wise the W124 is definitely more comfortable than the BMW, but older german cars still ride better than most new cars today.
To apply classic, firstly the car must be 25 years old, then you must first have 2 cars registered under your name, excluding the 3rd car.
The engine, chassis and interior must be original in order to qualify for classic and get that 80% road tax. Every 3 years the car must be sent back to JPJ and do inspection.
Hope this helps!
So if you refurbish the interior, for example rewrap the seats, door panels, and steering with new materials then cannot qualify anymore? Coz most of the time the original leather has all gone bad already by now.