Thanks for a good ride Andrew! The roads were great!
Here is a link to the clearview site. Looks like they are about the only ones I see that still make taller and wider windshields for the IS.
http://clearviewshields.com/shop/product.php?id=34They have them up to 6" taller and 5" wider than stock. Yours is 4" wider and 2" taller.
Hope this helps you decide on what size to get...