So, that means the pump moves up and down in the tank, depending on how much fuel is there.Get real, the pump will pick it up with an overflowing tank. That's why there are filters in the system, on the pump itself, and before the fuel rail.
The R32, at least, has a sort of surge tank built around the fuel pump area to reduce the movement of fuel away from the pump pickup. Hammering it probably is not condusive to keeping the fuel near the pick on a lowish fuel level. And considering the tank is much wider than it is deep, a 1/4 tank is not a lot of fuel.
Fuel surge will be most noticeable on RH turns, since the pump is located towards the RH side of the tank, and a RH turn will throw the fuel to the left, away from the pump.