S54 idle on cold start

Question on S54 cold start idle

I recently bought a used 06 Z4M with low miles (11k now). On cold start the rpm rises to about 1200 and blips very briefly between 1000 and 1200 before dropping to an idle of about 800. Also the idle vibrates just a tiny bit (enough to be noticeable). My service advisor says this is normal for an S54 engine but I'm not so sure. Is he right?

I've never owned an ///M car, but I've heard that the idle speed you have described is normal. As far as the vibration, I can't really say. It is, however, a highly-tuned performance engine and a little bit of a vibration may not be out of character. Does it run rough at any point in the rev range?

I've never driven a stock S54 equipped car, but my S38 definitely behaves that way.

Thanks for the response! The car does not run rough at higher rpms and once warmed up a bit it does not do the initial rpm blip. This is also my first ///M and I was mostly comparing with my other e46 325i which has no visible vibration in idle at 120k miles.