Bernard,
You are going to be taking a risk by using performance rubber in weather that it is not intended to be used. It makes no difference what car is using this tire since winter traction will be the same regardless. If you plan on keeping the lexus for a few years, I would suggest getting a decent set of winter so that winter driving will inspire confidence. Also, keep in mind that 1 minor accident these days will probably cost more then a set of winter tires when you factor vehicle damage, insurance cost increase and the inconvience of repairs.
experience.