I'm not sure it's working for me, I don't see any special network activities in Firebug while using the website.
Also, you should take into account the focus event of links, I tried and it seems you doesn't when trying on the "click test" page to tab tab tab on the test link and then hitting enter.
I don't know how instantClick is implemented, but to me attaching some callback to a second event is not added complexity, it's just a few duplicated lines of "administrative" code.
Also, you should take into account the focus event of links, I tried and it seems you doesn't when trying on the "click test" page to tab tab tab on the test link and then hitting enter.