I have the MBRP catback installed on my car, along with secondary cat delete. I have zero drone at cruising speed in any RPM, however the exhaust does hum if I lightly accelerate in higher gears at highway speed without downshifting. I definitely wouldn't consider this drone or anything near it though.
I've had other vehicles with different aftermarket exhaust setups that did drone so I am all too familiar with it. I see your user details mention a Porsche 996 with an LS3. If this is the car you are working on, the target RPM range of drone could vary. I'm assuming your overall exhaust length will be much shorter than a full length catback. There was a lengthy thread at one point on Camaro5 where users were testing different lengths of helmholtz pipes that may be more useful for your purposes. Thread links here:
https://www.camaro5.com/forums/showthread.php?t=102075
https://www.camaro5.com/forums/showt...ight=MRT+drone
I will try to get you some measurements on the MBRP resonators and pipes in the next few days. I would say for rough estimate though the resonators are approximately 4"-5" in diameter and 12"-14" in length. The pipe that connects the 3" exhaust tubing to the resonator appears to be 2"-2.25" in diameter.
Good luck with your build! I attached two pictures of my exhaust prior to install just to give you an idea.