I don't know about the chassis flex thing, but I've read that some weight transfer is desirable.
The FWD car is soooo weight biased to the front that transfer of weight to the rear will not necessarily hurt it and it can supposedly help with the launches.
Figure a rear wheel drive car is more like 50-55% front but on takeoff probably 60% or a little more in the rear and will increase traction. IIRC it has to do with the type of setup on the FWD car, i.e. macpherson struts and the like.


Former owner of '99 CSVT - Silver #222/2760 356/334 wHP/TQ at 10psi on pump gas! See My Mods '05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red '06 Mazda5 Touring, 5spd,MTX, Black