How did you break the car in and seat the rings? What driving method did you use? This business about the car already being broken in when you get it, I have found to be total BS based on my experience with my Z06.
Tail-pipes were sooty as hell for 2-300 miles, and I didn't check the oil from the factory (should have
) but when I finally did at 585mi, it was 1/2 qt low. By then I had seated the rings properly, changed the oil, and in 2000 miles since it hasn't burned an amount that could be seen on the dip-stick and even after hundreds of miles the tail-pipes are not sooty.
My method:
Gentle around-town stop and go driving until I got to the freeway.
On the freeway: Cruised up to speed limit, put it in 4th gear, let it drop town to 20 under (with noone around) and then accelerate strongly, but without flooring it, to 20 over (I don't advocate this...). Let it coast back down.
Anyway, I did that a good bit over a few hundred miles, passing people, playing with it, etc. and after a while began using 3rd gear, etc.
The main thing is to load the rings through acceleration and deceleration in-gear without going much over about 4-4500rpm or so. This is plenty sufficient to seat the rings.