Aaron. Yeah idk. I'm feeling sikaflex might be a good option. That stuff sticks awesome.
Go for it, i used it also. Marine grade black is what i used from Bunnings. Give yourself the whole damn container to get it on there. Tape it up with masking ensuring the middle left and right sides of the diffuser and get your brother, your dad or your sister to hold it up so it sits flush when taping it up or else it looks dodgy if not done right. Go hard on the tape so it holds lol.
Pain in the ass i know but ive been there and thats the only way to get it done. Leave it overnight as a MINIMUM, maybe bit longer. Its also easier to get the car on jack stands at the rear and unbolt your diffback mufflers so you can get the glue and diffuser contacting in your exhaust cutouts, make sure the glue is on the contact areas since there might not be that much, but where it does contact it should hold. Ive had no dramas.
Let me know if you need a hand.
