The IS300h has a 'snow' mode but it is rear wheel drive and the Lexus sales man actually said it is not very good in the snow. I have not had to drive it in the snow yet.
The engine noise is not aggressive sounding at all, even at high revs. Although the outside sound is well dampened. There is also a 'fake' engine sound option in the *****-pit but I personally don't like it. More details here: http://www.lexusownersclub.co.uk/forum/topic/84006-engine-sound-simulation/