let's get to the bottom of this "holes in the muffler&q

[JIBTEXHNKA]

i know, i know, search the boards. i searched them, i searched them again, and i searched them a third time. then i searched again, and i've narrowed the possibilities down to 2:

1: many informative threads are too old and have been deleted
or
2: we have very different views of what constitutes "beating a topic to death."

i was hoping we could have a comprehensive discussion about this; maybe consolidate all the information into one thread and then sticky it so you won't get people asking the same thing every other day.

so here is my question, or rather, here are my questions:

what exactly is the material you're drilling into? how deep is deep enough, how deep is too deep, or are you just piercing the external shell and it's hollow inside?

what patterns/hole sizes/etc have you tried? what sounds good, what sounds bad?

what are the chances that a muffler that sounds good to one person might sound horrible to the next (e.g. "it sounds like a muffler with a hole in it")?

does this modification negatively and significantly affect performance (because of lack of backpressure, etc)?

if so, are there ways to avoid this without needing to make other adjustments?