Is all your content served through your VPS, though, or the Incapsula service? You shouldn’t really be seeing a high TTFB on static resources, because there’s hardly any backend processing involved.
I ran a test from the Dulles, VA instance and the results looked much better, but now I see your website is undergoing maintenance, so it’s probably no use to make a comparison.
The favicon is not the issue, by the way. It’s just that it’s the last resource to be loaded by the browser before the “Document Complete” mark. You’ll want to find out why that Incapsula resource is loaded so late, though, if that’s still the case in later tests…