A great free tool that I like to use to test the performance of my websites is loads.in. This tool will tell you how fast it takes to load your website from different locations around the world. As you are nearing the end of your development lifecycle you will be keen to ensure that your caching strategy and the page load size of your site is within expected levels.
Loads.in will also provide you with a view of all the elements that make up your pages by going into the waterfall chart mode. This is useful for seeing how large individual elements are (such as images or CSS files) and also for highlighting any missing files (by spotting 404 errors).
Ektron CMS hints & tips 