Originally Posted by Fubarsky
I'm doing the same thing with Cyba's quad diffuser just like yours. I have not installed mine yet as I am waiting on the quad tips from RennArt. I would be interested in seeing your cut out prior to installing the diffuser and how you handle the lower bumper supports. I will post pictures of mine if I get it done first for you, but one of us will be first and it could be helpful to the other.
Here ya go. For the diffuser to fit flush with the rear bumper I had to make a cut between the tail pipe openings just below the crease, cutting the lower/middle part of the bumper out.
Here is the material I cut from the bumper....
This is also necessary if you don't wont the bumper showing through the lower horizontal diffuser vent.
The lower bumper mounts or brackets have to be bent in toward the middle of the car to clear the Quad pipes & reach the new position of the Diffuser. Here circled in Red is the original position of the lower bumper mounting brackets before I bent them inward. Also pictured with the 4" tailpipes before Quad Tip install.
A Dremel Tool works Great for making these cuts quick work. I used their new 1 & 1/2" "EZ-LOCK" Plastic cutting wheel.