Originally Posted by ShamelessCookie

Shifting as fast as you can from 1 to 2 and 2 to 3 often causes a loud CLUNK from the rear differential... this is normal, but it is not necessarily the best thing for the drivetrain.

You're putting a lot of stress on the rear diff when you shift that fast, and while it may be able to take it for a while, you'll eventually break something.

Do yourself a favor and keep it under 4500rpm until you hit 600 miles, then keep it under 5500rpm until you hit 1000 miles.

But by FAR the most IMPORTANT thing when breaking in a turbocharged car is to 1] Let it warm up before driving (at least until temp needle is above minimum) and 2] Do NOT hit boost or exceed 3500rpm until the temp gauge is at norm. If you hit boost and the turbo is still cold, you will regret it.

Now, conversely, you should ALWAYS let the car idle for at least 1 full minute before you shut it off... when I broke mine in, I would wait a full 2 minutes after every trip, even short ones, to make sure the oil in the turbo reached a safe temp.