We did not. Dh is a certified car seat inspector. The seat savers have never been tested with a seat and they can cause slippage even while standing still. They prevent the seat from gripping the way it's supposed to and can contribute to failure of the seat and/or injury/death in a crash. It is not recommended to use them with any seats at this time - therefore we never have. Our leather seats are none the worse for wear either.
Re: Did you use a seat saver/protector under your carseats?