There is no need to remove the windshield. Almost all of these repairs have been done with the windshield in place. The instructions do not call for removing the windshield.
It may be easier with te windshield out of the way, so if you are replacing the windshield anyway it may be worth the effort to arrange to install the kit while the windshield is out of the way. The windshield installer may not like waiting for you to get out of his way though.
