Flash, go to this thread:
and you will see a link to a PDF that indicates the transmission gearing difference in the 1LE transmission vs. the SS transmission. The 1LE gearing does take away some of the advantage of the bigger rear end gear. Keep in mind that the gearing change was to help the car on a road course, not a drag strip. That being said, the video I have seen of the 1LE vs SS shows an extra shift required by the 1LE to get through the end of the 1/4 mile, so there is still some advantage to the larger gear. I would assume that the larger tire is allowing for a harder launch, which will carry through the entire 1/4 mile. I also assume that the lighter rolling weight with the ZLI style wheels is also a bigger benefit than you are giving them credit for.