theres more than weight to do with this... its called physics... the engine in that spot shifts the center of gravity lower and more front along with doing a bunch of other things... making understeer even worse... suspensoin setups can help counter act this
with axels and everything... the way the car flexes and bends alot of things you need to think about other than just the motor and power

just some things to think about. do some searching on this.