I don't think that's a good size for the ITR. Outer diameter is too big. Plus they're $19/tire more expensive than the stock size.

The recommended pressures of 35F/33R seem to work fine on the ES100 in the stock 195/55-15 size.

But I agree - any lack of traction at this time of year is probably due to cold temperatures. Summer tires (like the ES100) are designed to be used in warmer temperatures. In February, winter tires will grip much better - even when the roads are dry - because they are designed to be used in colder temperatures.