No. Firepush code loads asynchronously, which means it will never block or slow down other parts of your website. Web page analysis tools might show you that Firepush loads after other apps, but that is how we intentionally designed it.
Your page load speed will not be impacted by Firepush, because Firepush assets are not on your site’s critical render path. What’s more, images and stylesheets are delivered by a global CDN to keep load time to a minimum.