I've used a derestricted moby pipe, which was awesome! But you have a puch. I made a jammy sidebleed, noticed a little boost. Like Maize said.. It's a smaller pipe which is why it works so well with a stock/stockish motor. I made a proma warrior... it rips pretty good. Added a lot of pull at the top, nice midrange to top end. Now, I'm running a Ninja G3 and it's tip top. All in all... Your bike isn't kitted, but you will eventually. I would go with the proma or a tecno circuit. The cones are nice shapes. If you go with a big fat pipe, I think you will be unhappy until you go with a larger kit. They won't be able to get into the range needed to get the desired power. So, sometimes, a smaller coned pipe is all one may need to get a little more MPH.
The wiki is a great read and good info... but only for it's time. There are so many different types of chambers out there now. We aren't even really talking about hacking and welding.
Graham is smart. Sound is important for sure.