I had the dealer install the upgrade chip during warranty service. Basically, the engine revs higher in lower gears and shifts more agressively. I was concerned that this would affect my MPG but it's possible that this power range is as efficient or even more efficient than the prevous one because I can't tell any difference. One thing that bugs me a little is I had to change my shifting technique to force an upshift after coasting by very quickly moving from N through D and left, then forward. I mean VERY QUICKLY. But it works and the car is overall better in traffic with no discernable difference on the highway.