Very roughly every 100lb is a MPH and .1 in the quarter when removing weight from the vehicle body removing rotational weight from the wheels & tires is a different story since the power is being used to rotate/accelarate the wheel & tire directly a little weight loss here goes a long way.
__________________
Brad
1997 Eclipse Spyder GST 14.1 @ 100 MPH
1991 Eagle Talon AWD (HOW) 11.574 @ 115.29 MPH
1990 Plymouth Laser RS-T (Organ Donor) 13.19 @ 110 MPH