I finally made up my mind and picked up some new tires last week. I've only driven my car twice since then and it has gotten way colder, but I think I'm pretty happy with my decision.
I HATE shopping for tires, HATE it. "Get these", "No these suck", blah blah blah. I ended up with a disgusting deal on a set of 245/40/18. Direzza Sport Z1 Star Specs. Up from the 235/40/18 I had before. They make my INVOS look like magic cock pony. They seem to run a bit wide, I just have to keep an eye on the GTO front strut rub now.
I know I need to get some mileage one them to burn off the release compounds but so far so good.
From a dig they are about the same as my INVOS in the summer... flipping useless until into second gear. Keep in mind, cold tires and ground. I'm confident once it warms up and if I had some heat in the tire they'll hook decent. From my 30mph roll (warmish tire), something cool happened..... it sort of hooked. It was pretty cool.
Keep in mind my GTO is light as a feather and HIGHLY modified, so YMMV. I should definitely be out of the 14's now