This is how I generally work with my customers. I will audit every parts of your website and provide a list of recommandations that will be much more relevant than any webperf audit tools. I've already worked on dozens of audits, for all kind of companies: media, e-commerce, banks, industry.
You have a specific need and you don't know how to shape it. I will assist you as an architect to build the right solution.
You like my open-source tools? I can provide support to install them, to use them or to adapt them to suit your needs.
A collection of webperf related tools that I published on GitHub.
Yellow Lab Tools: audits a website for performance or front-end quality issues (you need it!)
SW-Delta: smart browser cache that only loads the diff of a file when it's modified
SVG Image merge: non-vector image optimization with the SVG format
UX First: tiny JS that detects the slowest users
(Incomplete) list of technologies I can help you with