In Ohio they plug into the OBD port, if there are no codes you pass.
I don't see any codes when I scan for them running my 93 octane tune, I don't think they would find anything different.
It's going to depend both on the tune, and on what the test is checking. But if, for instance, it checks oxygen sensor status and sees it offline, that's going to be an item fail. Whether or not that's enough in a given state to fail the emissions is a state-by-state question (not sure how this works in Canada for our friends up north) but I'm just saying even if they don't check the tailpipe I can see how the obdii alone could cause a failed test if you're tuned.I'm with these guys, ALWAYS return to stock before taking it into a mech, dealership or state inspection facility.