Wehkamp boosted the pagespeed of their productpages after taking part in a Google Speed Race and ending up second. They published their score and findings using LinkedIn.
As I thought there was more room for improvement, I did a before and after comparison. This resulted in mobile improvement of 0.7 seconds when it comes to the moment of user engagement and thus First Meaningful Paint metric.
I ended up showing them my findings and technical improvements. As researches point out, even small changes can lead to increasing your conversion.