haha, yes i have spanked z's and they aren't that quick. i have also driven on a 4.4 and a 4.7 and a 4.9 final drive with itr gears and with ats close ratio gearsets. my setup isn't much different than yours, but my kit is tuned. i'd say go get your car dyno'd or something. what you are posting just doesn't register for me due to the fact that it's contrary to my own personal experience.