Could I borrow it after your done to dig up the yard.
What they mean is, there is no such thing as an off road cat.
Are you talking about getting high flow cats or high flow mid pipe, This is just a mid pipe with higher flowing cats than stock, or replacing your stock cats with higher flowing ones. These are often called catted h pipe or catted x pipe.
Or an off road mid pipe, like an off road x, or off road h pipe. These are mid pipes with the cats removed, or removing the stock cats and putting straight pipe in its place. These are often called an o/r x pipe , or o/r h pipe.