1. Use a CDN that supports ESI, like CloudFront. 2. It's not that much of a difference, after gzipping, which you surely already do. 3. See number 1. Moreove

1. Use a CDN that supports ESI, like CloudFront. 2. It's not that much of a difference, after gzipping, which you surely already do. 3. See number 1. Moreover, in the end, you'll get a less heavy document to be processed by the browser. I swear my all bells and whistles i7 X1 Carbon still struggles on some javascript-heavy sites.