Why do you want to replace them? Are they cloudy? If that's the case there is an easy fix.
Go here: https://www.youtube.com/watch?v=rXHTXdlWw1w
and a better more permanent method is here:
https://www.youtube.com/watch?v=UEJbKLZ7RmM
RepairPal Certified shops can diagnose and repair your 2007 Lexus SC430. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.