The areas it baulks at are things I can't do much about - like third-party JS etc. It'll also probably drop a bit once it is under load and has the respective ads and Viglink markup added, but that's a pretty impressive score.
It visually renders as quickly as my IPB site, and I expect that will work a bit quicker once it is the "root" site and isn't being knocked about by the IPB redirects I currently have in place.
Don't get too hung up on shaving parts of a millisecond here and there if your site is already fast. There's only so much you can do, and if your visitors are happy, and you're happy, and your server load is nice and low - then consider it a job well done.