Once you have a stable code base you could consider compressing JS files so that your new customers get your site downloaded even quicker. Our CMS websites rely heavily on AJAX and JavaScript as do all modern interactive websites that have been designed for users to customise and update.

There are a number of ways of enabling various forms of caching and compression but a quick win could be to use a tool like the JavaScript compressor to give your site a little more zing. It will shrink a JS by about half which could be several 100K if you are using a modern library.