I would say lowering weight in certain areas will help more than others.
if you can lose 10 or 15 lbs of rotaional mass you''ll see more gains than losing the same on just mass.
HP is lost through drive train, if you can improve drivtrain, more HP will get to the ground. plus losing overall weight.
Wheel weight, chain weight, non-oring, ceramic bearings, tire weight, synthetic oils, free up brake pads, etc.
I heard 10lbs mass=1hp, dunno if thats accurate.