I wound up using StatCache. I forked it and made a PR that adds an option to minify the HTML when written to the filesystem.
https://github.com/opengeek/statcache/pull/27
And I got my perfect page speed score!!!
$this->modx->resource->_output = preg_replace( array( '/ {2,}/', '/<!--.*?-->|\t|(?:\r?\n[ \t]*)+/s' ), array( ' ', '' ), $this->modx->resource->_output );