Alan, you are right. It's the extended oils service that caused these problems. I have an 2002 E46 with N42 and only genuine 102K kms. It runs perfectly and had none of the issues that many people encountered like white/blue smoke, engine rattles, sludge etc. My pre-purchase check with Auto Bavaria reveals that the previous owner only did 2000 kms in first 5 years of ownership. Despite the very low usage, he serviced the car every 6 months. Thus this has avoided the prolonged oil service of 20-25K which was the norm then.
Wear & tear maintenance parts like thermostat, water pump, LCA bushes, absorbers will require the same treatment depending on how one drives the car and what maintenance schedule is put in place. it's just like any other BMWs.
E46 N42 are getting very cheap due to "wrong perception" that the engine is problematic. If a good one do come by, I wouldn't mind picking up another unit for my other daughter. 1.9, 2.2, 2.5, 2.8 or 3.0 all have their own share of problems.
The tip is to have regular oil service 7K - 8K kms using good quality semi/fully synthetic. Note : never allow the mechanic to put in more than it's necessary. Keep the oil level between the marks indicated in the dip stick. In my case 4 L will be sufficient and no top up required until the next service. Mechanics like to over fill thus charging you more. BTW I also don't have any problems regarding topping up the radiator coolant. Just make sure to inspect those hoses every time that car is serviced.
Parts for parts, N42 do cost more than those with M43 or M54. It's a BMW, so if we are buying one we just have to be prepared in maintaing it like a BMW.
