The tick is undoubtably the oil crossover pipe. The good news is that I have fixed a number of them that went through additive treatments for long stretches before repair (from previous bad advice). it doesn't seem to hurt anything.
As to whether you should be a BMW enthusiast or not I can't say, but if a 97 E420 turns you on you just haven't experienced an E39 540i. The power can be close to the same with either car. the sound and feeling of solidarity could be near the same, but the presence on the road is no comparison. R&T just found the E39 to be the best car they had ever tested.
Having owned one for near 2.5 years I can say that for most purposes I would rather have the MB (I have owned dozens of MBs, a number of Porsches and two BMWs). But for driving the comparison is between these two cars and everything else as they are a world apart from everything else.
Bosch Master, ASE Master, L1
33 years MB technician