Starting to dislike my diesel

In 1964 when I was 11 my dad bought a 1959 190D. I really liked that car and hoped that one day I would be able to buy my own diesel. Well it took a while but three years ago I bought a beautiful charcoal black 1993 300D 2.5 Turbo. It had come off a lease and had about 83K on it. I have been really happy with it up until about six months ago. I drive it very easy and watch the maintanence very closely. I thought this car would save me alot of money on fuel bills since my commute is 84 miles round trip. It has saved me money on fuel, I have been averaging 33 mpg. About six months ago until recently it has been in to the dealership for repairs at a rate of about every three weeks. Glow plugs twice, cruise control, heater fan, airbag sensor, belt tensioner, alternator (cars third alternator). I dislike GM products but my brothers 1998 Camero has 200K on it and still the original alternator. He bought a new spare one for $105, Mine was $400. I have also had to replace the tires, shocks and muffler which I expect is normal for any car with 158K that my Benz shows.

Anyway my point being is that even though I have for the most part loved my diesel (the sound, smell, power and the quality of my surroundings) my fuel savings have long disappeared with my repair bills (average $120-$1100 every time I take it in) Have I expected to much from this car?The mechanic told me that my diesel is one of the finest he has seen ie. no oil leaks, quiet, runs well, it's just that everything else around it is going to hell. Each time I take it in I hope that this will be it for a while but as busy as this dealership is the service writers know me immediatley by name. I asked my wise young GM brother about it and he tells me that either a person pays up front (new car) or you can pay as you go (used car). Maybe there is some wisdom in that. I have about $27 K into it now (paid originally 18K) but this is alot less than if I were to have bought a new E300.

Despite all this I will be looking at a 1960 190D like my dad had 27 years ago but I will not be expecting as much out of that car if I buy it vs. my present Benz.

Thanks for letting me bend your ears,
Mike