Mine don't touch that guard, I didn't have to modify it at all for clearance either. I have the 4-2-1 model. I think the buzzing sound is just the thin steel they are made of, which resonates to the exhaust flow.

Mine are marked Forza.

 

I had the 4-2-1 header with a custom exhaust with no resonator and I buzzed all the time. When I put in the KRD exhaust and kept the 4-2-1 header, the buzzing went away.

 

<div class='quotetop'>QUOTE (Raven997)</div><div class='quotemain'>was the gb for both?</div>

The GB is currently sold out, dont know if hes getting more or not, anyways heres the link, maybe they will get some more soon.
http://www.rdtiburon.com/forum/showthread.php?t=5734

 

how does the krd exhaust sound? i heard that video clip of op and i liked that sound, o and where ya get it?

 

It doesn't sound too bad, but I will be putting glasspack to keep the noise down. I will keep everyone updated how it all goes.