I have noticed same glare issue with my IS 250 / 350, while driving especially between morning to afternoon times. Early evenings onwards this glare is not that noticeable. I solved it with two methods: Used legally darkest possible TINTING and I am now using a POLEROID sun glasses. Any other sunnies wont give proper results like sunnies from POLEROID. Try these and hope this solves glare issue in IS 250/350.