Emissions testing is different from region to region. California has some of the strictest emissions laws around, for good reason I might add, so what applies to California might not or will likely not be the same in Canada. I know in some Provinces and Cities in Canada, tail pipe emissions testing is not required, but in some more metropolitan areas, testing is required.
For some background info before answering the CSL header emissions question, I'm guessing Canada receive cars that are classified as ROW (Rest of World) cars that are slightly different than cars shipped to the continental United States. All US cars have cats incorporated in the M3's headers, making the Section 1 of the exhaust, the segment immediately after the header+cats, just a straight through pair of pipes, with the exception of a small resonator incorporated into only one pipe out of the pair in the Section 1. ROW cars, like the kind Canada likely receives, would be like the European cars, meaning cat-less headers that are more free flowing, and then the cats are located in the a Section 1, to clean up tail pipe emissions.
The likely answer to your question, I'm guessing Canadian M3s probably have (cat free) headers on them already. As for headers, weight is the only difference between CSL and Euro headers; the pipe diameter is the same. To confirm header type, just take a look at a M3 and the answer should be obvious.
Last edited by lucky_doggg7; 11-14-2012 at 08:09 AM.