The munchkin code we have installed is slowing our load time to almost 5 seconds per page which is frankly unacceptable.
You need to be more clear about which part is causing the delay (bootstrap, library, hit logging) and provide an example URL.
Also, please move the post to Products (Community is for questions about this community/collaboration app).
Are you using the asynchronous code? That may help.
"It is highly recommended that the Asynchronous tracking code be used for embedding Munchkin on external pages. To ensure the highest possible success rate for execution, embed the Asynchronous tracking code in <head> of each page."
"Highest possible success rate" is a strange expression, since it's really "Lowest possible interruption of other page and page asset load activities."
You use the all-async mode when you don't want slow/failed loading of the bootstrapper to interfere with other stuff, not when you want activity logging itself to be any more reliable.