I've been in & out of Canada a lot (Mosport...LCMT...etc), with titled and untitled cars, and have never ever had anyone ask about title. Bigger issue is likely the old Form 4455 thing - the "export & re-import" thing...they've probably changed the form now - you should declare it upon leaving...and then you won't have any problems bringing it back in. What's interesting is that I have a gearhead racer friend who is a US Customs & Immigration officer, and he's always told me "don't fill that 4455 crap out...we hate that...it's just more paperwork for us...we see racecars at the border all the time...it's not a big deal".