>> When you move your site to a server across the globe, it will adversely affect performance.
If performance is such a concern, you really should be looking at a CDN to deliver static data as that is usually the bottle neck.
You can also look at some basic things like ensuring your common JS files like JQuery etc are loaded from community provided CDNs like Google etc.
CDNs are pretty cheap. We deliver through Softlayer and have a backup at Amazon. If you configure your CDN as an origin pull, you have redundancy and are paying only for bandwidth used.