Bolt on Catalytic Converters...where can I get them?

I have a 2001 GT and a VRS off-road X-pipe. I am getting the car lowered a bit to get rid of the 4x4 look. With this, it will be almost impossible for me to remove and replace the X-pipe for state inspections so I was thinkin that instead of shelling out a couple hundred bucks for an off-road x with cats, I can just modify mine to be able to easily swap out a pair of cats.

Anyone know if they sell bolt on cats? Any help is appreciated.
 
How does lowering your car effect your ability to swap the mid-pipe out???? As long as you can jack it up and put jack stands under it, what is the problem? At worst you'll need a low profile jack @ $150.