Don't know exactly. But the hole should be about half the size of a pencils diameter. Side note: I highly recommend drilling into the Roush mufflers also. They can literally turn to cracker crumbs with rust.

 

Where do you guys recommend putting the hole? I have Magnaflow streets and they have slighted tips so I never thought I needed it.

 

It's your call depending on your mufflers shape and how they are installed. Look for the "center of gravity." ...and where the water would pool. It's usually around the inlet or outlet. Don't drill a hole in the middle of your muffler. Lol just a TINY inconspicuous weep hole...

 

Ok, Thanks!

 

Thank you. Tuned! I run several tunes but mostly a custom 93octane race version for DD.
OP i have no experience with the FlowForce, but I did ask a gentlemen at a local show, with manual, he has the drone on highway as well. He is considering additional resonators, I will keep you updated if I hear him again.
If your looking for a replacement, at a budget price, I would suggest GT500 muffs.
I bought a pair brand-new from American Muscle for $300 shipped w/discount. Here is clips and in car exhaust notes.
With headers and frpp xpipe.

 

This is a rear shot of the stages of my exhaust build. I was thinking of removing my factory resonators, because I still want a little more sound. I have decided to go with high flow cats instead. That should change the sound slightly and increase more flow.
Any input is appreciated.

 

Whoa, I'd buy those in a heartbeat if I could get that sound for $300

 

Part of his sound is from the BBK Shorty headers and FRPP Cut and Clamp X-Pipe.
I have had people say they like the sound of my Type S Borla's, to bad I have the Touring, like him I have the BBK Shorty headers and X-Pipe.