general problems of the 2003 Mercedes Benz C320

I purchase my 2003 mercedes from carmax in 2 years ago. It had 45,000 miles when I purchased it. From the time I purchase this car I had to replace the sunroof motor, replace the shocks, replace the truck lock, replace the fuel tank, and I had some transmission work done. My biggest problem is having to replace the low beam lights every 6 months. I suspect there is an electrical problem, but cannot completely prove it with the manufacturer. With 1 year, I had to replace the bulbs 3 times. I had to replace the front low beam bulbs and the brake lights. This is surprising since this car (under my ownership) has never been in an accident. I am so disappointed I purchased this car!.