You could always just buy a normal pan and add the baffles yourself, easy enough job to do.
Do you get the extremes in G force in drifting that you do on track? I appreciate you're sliding a lot, but once the car has settled force will be minimum. Transitions are supposed to be smooth (I think, please correct me here!), so G force changes again shouldn't be massive.
Usually people get pickup problems when they buy a regular car, then chuck stiff suspension and super sticky tyres on, then go tracking. With slippy tyres in drifting, I would imagine you'd be miles from trouble.