I bought the Ford Racing Trunk liner. I guess there are some support braces in the trunk near the back of the car, near the taillights. You simply cut along the existing lines and it will fit. I already had the Ford all weather floor mats with the Pony logo. The Ford Racing trunk mat has the same logo.
If I have to haul stuff in the car, that means folding down the rear seats and sliding stuff through the trunk. I like the FR liner because it doesn't have much of a lip to catch on as I slide something forward. On the other hand, the Weather Tech (or Husky) liners are designed to contain water, so they have a very pronounced lip on the front.