A couple of questions re my new C55:

1. Having now completed the break-in, I'm really enjoying the acceleration, but do not have the launch challenge others talk about. I can floor it in 1st gear and will get a "chirp" from the tires, but that's all. I thought from reading other posts I would have "problems" controlling wheel spin. No such luck. Could it have anything to do with the fact I live in Calgary, which is over 3700 ft. above sea level?

2. The engine makes an annoying noise at around 3500 rpm or so, in particular before the car has warmed up. It is a rattling sound. I'm not very mechanically savvy, so I may get this description wrong, but it sounds like noisy tappets. I did not notice this noise until just at the end of the break-in period. I did push the acceleration hard once just before the 1000 mile mark and noticed the noise subsequently. Have I damaged the car somehow? Anyone else with this kind of problem?

Thanks for your help!

I didn't think you needed a break-in period. When I was test driving the car at the dealer, he let me pushed the car pretty hard, so I don't think you need a break-in period. Most high end performance cars are tuned to take in the extra speed from the get go.

In my car, it depends how "fast" you floor the car. With ESP on, I too can just get a brief "chirp" before the car accelerates off if I don't floor it as quick as I can. If I stomp on the pedal as fast as I can with ESP on, the traction kicks in and temporarily cuts the power before accelerating off.

With ESP off, you should be able to burn a bit of rubber before accelerating off if you stomp on it as fast as you can.

haha...he let you push it because hes not going to be buying it.

all cars, well majority of cars, need break ins. from audi to ferrari, cars need to be broken in. unless you want to have a ****ty engine later on. heres a newsflash for ya, even an enzo is recommended to be broken in

I get the same noise before the car is fully warm. I'm thinking this is normal as I've heard other people experience the same thing.

Put the car in M mode and turn off the traction control next time. Your wheels will spin like your on ice.

Just be sure to watch those RPM's!(Seriously)