4DRHTRD's slicks are 26" tall. That is 3" shorter than the stock 29" tall 255-45-20". This would mean that he has an adjusted axle ratio of around 3.52, vs the stock 3.16 and 29" diameter tires.
Virtually all of the extra weight in the Flex is in the back half of the vehicle, so the weight balance is better in the Flex.
Generally speaking, the Flex is about a half second slower than a comparably tuned SHO. Not sure any SHO owners are using Nitrous. Those that spray 100% Methanol and have all the other goodies (before new turbos and downpipes were available) were in the 12.2-12.3 range under ideal conditions... (very low or negative DA's) NOT a 5,400 DA!!!!! My 3 - 12.9 Flex runs were with a 600 DA. Best was in IA when temp was 42 deg and when I was running 50% to 60% methanol. The other 2 were in Bradenton, FL at 75 deg running up to around 70% methanol spray, and Nitto DR's. 4DRHTRD is at least a second faster than my best, if he were running under the same conditions.
VERY IMRESSIVE INDEED!!!!!!