Reduce network bandwidth

You are working on a AJAX-heavy site, and your script files are separated in your solution by function. You have already implemented minification and bundling, but you are still getting reports of poor performance when users try to access your pages. You cannot replicate the problem locally. What additional steps can you take and still provide the same user experience?

Turn IIS compression on, disable dynamic page compression, and set the minimum file size to the size of your smallest bundled script file.
Turn IIS compression on, turn on the option to compress dynamic pages, and set the minimum file size to 0 so that every file served will be compressed.
There is nothing more to do without redesigning the site.
Compress all scripts locally and have the users download the compressed files rather than the uncompressed files.