Break it in the way you plan to drive it, after the first oil change. When I rebuilt mine I left it at stock boost levels from the git go, it's a fun car to me -- not a drag/ track car. I've seen lots of guys who plan to drag/ track their car just fire it up, change the oil and then rip it to redline. Some will tell you to take it easy rev to 4-5k and let off the gas and let the motor slow you down to break in the rings, that's kinda what I did -- take it as you will.