Being from Canada the law doesn't even apply to you so let me explain it to you.
1: The dealer/manufacturer has to supply you with a written description of how the after market part caused the affected part to prematurely fail; in order to deny your warranty.
2. If you believe their written description is full of sheet, you can take your case to the Attorney General, or to the FTC, which will review the case.
3. If you still disagree, then you can find a lawyer to sue. I don't know about Canada, but there are plenty of lawyers in the US who love to sue deep pockets without taking any fee from the complainant (i.e.: Jeffrey Fieger, Sam Bernstein, etc.). Matter of fact, they advertise no fee if you lose. If the lawyer won't take your case free, you probably don't have any legs left to stand on, or the manufacturer is about to go bankrupt negating the deep pocket.
Bye, I'm done with this nonsensical, stupid thread. It's gas tank not a supercharger.