Lemme try here...

1. Mobil1 15w50 would be OK. But I wouldn't go to a thinner oil. It may just be me, but when an engine gets used to a thicker oil, it's never good to start using thinner stuff (I speak from experience).

2. Don't waste your money on a factory CD changer. Rip out the factory head unit and stick an Alpine unit with built-in CD in the dash opening. A Volkswagen wiring adapter will work. Do a google search or two...

3. Yes. A good body shop can fix it without a single sigh or groan.

4. How much money you got? That's what you'll end up spending. Hint: The more the estimator moans and groans about how hard it is to do a Mercedes, the more you're gonna get screwed.

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'01 SLK320, '79 450SL & '01 C320 -- What? 3 Mercedes? I am DEFINITELY crazy!!!