You're right, Glenn
It was the muffler's fault. I had the muffler bolted on too far onto the catback, that when I went to bolt in the diffuser, the top of the platform was lodged up against the edge of the muffler. In my haste to go for a spin, my problem solving skills were at an all time low.
Im letting the car cool down before I go out and tackle the problem of unbolting the muffler and scooting it a hair to the passenger side. Thanks again for the continued help and for the diffuser. It looks absolutely sick!!!