1. As temp drops all your LCD displays will slow down and image changes will lag. It may not be evident at 10 or 20 Fahrenheit, but at -20 Celsius, it is apparent.
2. There's a another thread about that somehere. The consensus was crank up the heated seats and get a block heater. There is no easy way to do it.
3. The 4gr-fse develops much of it's power in the higher region of the power band. Because it's a small V6, it will easily rev up to that speed to develop the needed power and thus the noise. Also. lexus made a conscious decision to tune this car more aggressively than their usual geezer mobiles, seeing as the intended market is different.
4. Plenty. None will give you power.
On a side note, be very careful with the Lexus AWD and all seasons in winter. This is a heavily RWD biased car. The AWD and VSC mitigate that somewhat, but the back will come loose much easier than a FWD car, especially with VSC off. I spent the weekend on an ice covered race track and I can tell you that it can be handful when traction is limited. The point is, drive slow. AWD won't save you once all four wheels break loose.