What weight do you have moved to the trunk? Do you have any off the line pictures to see how much your Bu's rear is squatting?
If you can't use maximum power (nitrous) or any other little "adders" why run on the street, what kind of excuses comes up with everyone that their "potential" wasn't met? Is the strip too expensive or too far away to go for a day and see what full potential you and your friends car(s) have?
Do the frame notch anyways to be able to tuck the tires easier and let the rear squat more if you mess with the springs/shocks. Have you gone through the photo gallery of some of the off the line pics and the tires are up into the fenderwell quite a ways.