I thought about doing this when I had my old aFe setup. Have you really looked at the Hemi hat and seen what all it would take to do what you are wanting to do?

Here are a few pics of what the inside of the hemi hat looks like (I cut mine open trying to figure out the best way around it for another one I had).













Key thing to note, its not round so right off the bat you will have that issue to face. Second, cutting the pipe on the bottom wont do you much good as you not only have to fit the pipe in you have to match the ends and its not a normal 90* elbow in there.

Good luck if you want to try it, just have a backup or 2 (use one as a test and the other as the real thing and one just incase it doesnt work at all).

 

After that, I gave in and bought a vararam..... Runs a lot better now