I've been doing a good bit of research into website performance lately and I'd say I've gained a fair amount of knowledge about best practises to improve website performance as well as reduce bandwidth requirements by making such tweaks as GZipping, content caching, and image and script optimization.
My problem is I've found plenty of case studies from hugely popular sites such as Facebook, Google and Amazon but what I really want is some findings and figures for sites a bit smaller say 50-250k visitors a month.
I'm looking for what was gained from investing time into performance optimization e.g. significant speed improvements, reduced bounce rate, reduced running costs, and all the analytics stuff.