Last post is correct, but if you got 16" wheels it with, you can get away w/out snow tires...
The traction will be poor, but much better than the stock 17".
If you drive a lot in the winter, get snow tires.
Thanks for letting me know about previous forums about this issue, there are a lot of them to search in case you haven't noticed! It can snow a lot in Colorado and I just wanted to make sure that the IS could be a functional car in the snow. I just graduated from college and am looking to get my first car. I am leaning towards getting an IS300--my dad wants me to get a Maxima, which is a good car, but not as fun as the IS300. I think its a matter of age... Although he does have a 87 Supra that hauls ass with a modified turbo and exhaust. Anyway, I'm getting off topic. I love the site. Any ideas how to convince him the IS is the best?