I wanted to post my experience after finishing stage 3 on my '06 R*.
1st off.....thanks to Fatbike and everyone before me for posting this mod. I saved hundreds of dollars and achieved a result that sounds better than anything I could have bought.
After reading everyone's comments, I decided to go straight to stage 3.
I bought (1) 1 1/2in. metal hole saw and (1) 2 3/4in. metal hole saw. I also bought a dremmel tool just because it was a good excuse to get one and my wife went for it (Finally...I was able to use the rational that I was "saving money" against her!).
I decided to take the slip-ons off for this one and pulled up a chair to my saw horse.
I used the 1 1/2in. hole saw to seperate the cone from the center pipe.
Then I used the 2 3/4in. hole saw to seperate the center pipe and baffel wall from the outer shell. Side Note: The first pipe seemed like it took forever to get through so on the second pipe I used a punch (1/16in at 3,6,9,12 etc...) half way through drilling just to reduce the surface area and give the bit something to eat into.
Once the center pipe was free to wiggle, I took a concrete pin and inserted it in the pipe then moved it up/down/left/right until it broke free (took a minute or two).
I took the dremmel tool and grinded the few rough spots left by the hole saw.
Lastly, I started the bike, grinned from ear to ear at the sound, and took it around the block to rub it in my neighbors faces (all harley owners)

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I wouldn't say the pipes are loud, but they are noticable. The best part is the deep-deep throaty rumble that's gotta be the best thing I've ever heard (maybe I'm bias)!
All in all, the whole project took about 2 hours and a few beers.
Hope this helps!