Not sure who is watching this thread anymore now that it got moved but an update for what its worth:
Finally there has been a break with the crappy weather over the past few days and I've been driving the IS!!
Its been amazing!! The power is so much fun and it sounds super mean when that wastegate opens... yet still cruises around with a "slightly modified OEM performance growl". Makes an awesome sleeper Surprisingly its able to grip quite decent on the crappy all season tires that came with it in these low temperatures.
Drive-ability is about 90% of stock I would say. Theres a few small hiccups here and there that will be ironed out with street tuning as we go, but nothing major. Cold starts are no problem so far down to -10 deg C and same with warm and hot restarts. All in all I'm very pleased with how this turned out - its pretty much like stock just way more power and higher rev limit
I'll get some driving video if i get a chance as the car won't be out for very long (the weather is turning crap again).