The road from Osoyoos back to Vancouver would tax pretty any powertrain that is not a V-8, it is extremely hilly. It is also a perfect place to test handling, too. Not a road where you can take your mind off the road for an instant. Highway 3 is one road I avoid in winter unless I absolutely have to drive it.
As for the four cylinder engine offerings, with the CO2 regulations of the Obama administration set for a fleet average of 250 grammes per mile by 2016, we are only going to be seeing large V-6 and V-8 engines in vehicles that command much higher prices than the Regal.
Best of all is, I believe, the Regal is slated for production in Oshawa in 2012.