I've been through the import process a few times before, and I am aware of the requirement when LEAVING the US, which I think catches people by suprise. If I recall correctly it is 72hours notice, and at my "local" crossing they are pretty easy going, so it usually goes well.
Getting a 15+ older car into Canada is pretty easy, too, as long as you have a bill of sale, etc. and you don't mind paying A/C tax, 13% HST, and 6.1% duty. Aaargh.
Nobody familiar with 911's believes me when I tell them the A/C works but Bill Eason who did the ppi assured me it does - and he sounded suprised. So we'll see if it lasts through the Mojave desert..