Bought this CLK 430 cab new in 03. Barely has 10k miles, has had one service at MB store. Ever since new, it has had a substantial amount of valvetrain noise. I didn't realize exactly how noisy unitl I bought a used S430 a couple of weeks ago. When I realized how quiet and smooth the other car was, it put me back on this subject again. Problem is, how do I approach my delaer/tech about the noise? I'm sure they're going to want to get rid of me, but short of pulling up next to another similar car/motor, how do we quantify? What's the criteria for a lifter job? Wasn't this a fairly common problem in the 210 430? Main thing is, I just don't think the car performs as well as it should. It doens' thave as much power or get as good fuel economy as my last two 430's. In fact, this S class gets far better gas mileage and weighs probably 500 pounds more. On top of that, I'm a clean freak who's not too happy about my car sitting at the service department for a couple weeks getting greased and scratched all over. I think perhaps if I could get this issue recitified, I'd probably just be on my merry way. Techs/SA's at factory stores, how can I approach this without making an enemy or getting reputation as a pain in the backside?