I have been thinking..

Yes, itīs true..
I read and have heard that those running test pipes actually get less drone than the ones running eg 200 cel sport cats. Can this be correct? Or is it just the increased overall volume that makes the drone less obvoius?
If so, would you think that I could use my old 200 cel cat-pipes, just drill (and use general violence) out the cat-substrate and use this as test pipes? Or will the actual "bulb" where the cat used to be create drone or some other bad effects?
I run: ebay headers (no cats) and FVD sound version at the back.