Just curious, Are you cheering for the Impact because you want to see Canadian teams do well or are you cheering against the Impact because as a TFC fan, you always cheer against them?
In this context, I'm cheering for TFC to beat them. If they make the playoffs despite that, then I'm happy to see a Canadian team do well. Normally, in a game with Montreal vs. not-TFC, I'd be mildly against Montreal. The only time I'd actively cheer for the Impact is if they were Canada's representative in the CCL. But then it would really be Canada I'd be cheering for, not the Impact.
Funny, at the time that I posted this, I meant for the remainder of the season forgetting that our game this weekend was actually against the Impact. I am cheering for the Impact to make the playoffs and do well but I cannot bring myself to cheer against TFC when they are playing each other. Same position as Kingston posted above.
I'm cheering against the Impact. If it were the CCL I'd want to see a Canadian team do well, but not the MLS playoffs. That being said, now that TFC is officially out of the running, I'm cheering for all other teams to not make the playoffs. I know it's not possible, but it's still what I'd like to happen.