Well, me again. You can modify the cans quite a bit without remapping. You see, the real "restriction" in the Busa exhaust happens down where the header pipes come together. Take a look, you will see a "bulge" where the "restrictor" is hiding.
What I did was get a long drill (3/8" I think) and drilled two holes all the way through BOTH baffles. It made it sounds better. I would probably have done 4 holes in each one in retrospect.
Alternatively, I have a D&D system for sale on eBay CHEAP! Search D&D and hayabusa if you are interested. Those babies have got some sound!
Best Regards,
Doc