Things definitely seem to be a bit quicker. New keyword searches still seem to take around 4 seconds in Chrome and around 2 seconds in IE. Never thought I'd be saying IE was quicker than Chrome! haha.
I've noticed on my site, if I reload the page (tested with an without bypassing cache) sometimes it will load in a couple of seconds, sometimes it takes quite a while. So there's something going on. Whatever the issue is, it might be causing the slowness of the ajax search pro results.
I previously disabled all plugins, including mu plugins. Disabling WP Better Minify actually seemed to speed things up considerably! But maybe there's another issue somewhere 🙁