I’ve read alot about people debaffling their pipes. They use different techniques, one of them is to drill 8 holes in each baffle resulting in a deeper and louder sound. Some are very happy with the sound they get from this and some are not happy with it and there’s no way back once you’ve started drilling the crap out of your pipes so you better have a backup plan!
An alternative is to replace your stock pipes with a different brand. One of those are the Vance & Hines staggered slash-cuts. There are many different types of pipes out there that will fit the VN900 just perfectly, but I love the slash-cut look of the stock pipes so I’d like to keep the original look but wouldn’t mind getting a deeper, more fuller, sound out of my pipes.
If you live in the US you’ll probably find these alot cheaper on the aftermarket at eBay. If you live elsewhere or like to buy your stuff brand new the RRP is at US$390, but I’ve seen them online for US$390 and I’m sure you can find them at lower prices if you take a look around.
I’ve done some research and found some YouTube videos for you to see and listen to. Check ’em out:
Official Vance & Hines website: http://www.vanceandhines.com/products/kawasaki-vulc900-scstagg/slashcut-stagg.html