See if you can find some pics of your header and post them.....
The reason I say that is the Canadian ones are a tube type header that look alot like the Calmini one...they appear to be a fairly high flow design and they are not that expensive to buy new. That's why I suggested keeping the stocker and going with a good exhaust.
But if yours is a cast iron one then it's a different game and you might want to find the Canadian tube type one.
Zag