Find out for certain where your fore/aft center of gravity is. Weight ahead of the CG almost always helps ET, weight behind the CG is worth less and losing weight behind the bumper can even slow your ET...even if if picks up your MPH.
Reducing your unsprung weight and rotating mass is worth much more than body/chassis weight. IIRC a pound of rotating mass reduction is nearly equivalent to 6pounds of stationary mass. I'd highly recommend reading the Herb Adams book on Chassis Dynamics, Extremely insightful particularly regarding Monocoque vs ladder frame rigidity, ex: boxing in an open ladder with flat plate vs cross bracing can (in many cases) be stronger AND lighter than cross braced tubing. It's also very important to understand the cause and effect of drilling holes in structural members terms of dynamic load forces ( torsional/compression and beaming)
