Hi folks

I've been reading about breaking in a new or rebuilt engine and also about
testing your new plane.  The obvious conclusion is that they are really at
odds.  With a new plane, you want to gradually work up to full speed before
you explore the top end of the envelope.  The reverse is true of a new engine
in that it needs to be run at high power settings to seat the rings and
properly break in the cylinders.  So what do you engine guru's have to say?  
I've never done either break in, i.e. new plane or engine.

1.    Has there been a significant number of engine problems related to being
poorly broken in while expanding the flight envelope?

2.    One person suggested buying a used engine that was already broken in.  
Any idea what that costs and the chances of getting a lemon?

3.    And some very knowledgable people participated in a discussion a couple
of weeks ago about aircraft diesels.  How are they broken in?

Thanks for the help guys!

Dan