Do you need any special seat covers for the Prius package 9 to prevent interference with the restraint system. I know the curtain restraints are ok but what about the side restraint air bags. I need tan covers and yet I don't want to screw up the safety systems by ordering the wrong kind. Anybody tried any headrest covers or rear seat covers? I'd like to get a product that I can apply to the seats as a protectant but from experience I know that the two front seats should have protection from day 1.