OK all... It's been a long time since I have been two wheel bound. When I was young I grew up dirt poor and couldn't afford a car, so I was forced to ride a 1977 Yahmaha XS400D for three years! Snow, rain, sleet... You name it.
Now... Some 20 years after I purchased my first new bike! It's a VStar Clasic 650 and I have always known for years that loud pipes save lives! With that said here is my take on drilling:
1) My bike is two days old, but was WAY to quiet. To hell with the warranty, I can fix anything else myself. But I can't fix being dead.
2) Because of my living location... Straight pipes is just way too loud and removing baffles is a little extreme considering I still have to retest for my M endorsement this coming week. I don't want the examiner to say it's not street legal because of the decibel limit.
So here is my take on drilling:
a) To dremel the cone... Well due to divorce, I can't find my dremels.

So I had to drill cone and all!
b) The two pipes (high and low) are easy enough to work on while the pipes are on the bike... However the bottom one is a pain with a full size drill.
c) To get my holes started in the cones I tried drilling at an angle as well as a punch... The bit just kept scoot'n all over the place.
d) So I grabbed a 4-5 Inch outdoor wood deck screw, the really pointy ones and used that with the drill and the phillips bit to get a
pilot hole started in my four holes for each pipe.
e) After the initial pilot hole was in... Going straight to 3/8 of an inch was out of the question! I had to progress up every three bit sizes or so until I reached 3/8th.
f) One thing I noticed was... If you kept the drill on forward I would constantly bind!

So I quickly found out that reverse worked MUCH better!!!
g) Basically... Walk your sizes up a little at a time and drill at an angle... Sorta straight down on the hole and once in, rock it so the drill lines up with the pipe straight.
h) The hardest two holes are on the bottom pipe 3 and 6 oclock, with 6 being the worst!
i) After an hour... All the holes were in and I cleaned up the area with a round file.
The finished product was a very nice deep throat sound... A little growl without driving the neighbors nutso!
In addition.. While on the road, they sound outstanding!!! WAYYYY better than stock!
The only prob I found was... The bike kept moving on me, even while it was in gear!

So if your by yourself, park her against a wall so she doesn't scoot forward while you are drilling.
The only other mod I made to the bike outside of pipes was compliments of Pep Boys... That dern tail light bulb was just too damn dim.

Go to pep boys and get yourself a circular LED tailight bulb (20 bucks). It is SUPER bright and that extra 1/2 second may save your butt!
Be safe everyone and make it home to your loved ones! It's a dangerous world out there.
==ZOwwie