Before I get slaughtered by a tsunami of "It ain't meant for PvE BOI", let me suggest this :
Dont increase it's speed, or anything other than the following : its health. Let's say by 100%.
Its utility wouldn't be speed or its attack, but rather, its tankyness and the safety it would so provide while traveling.
I perfectly understand that it is an absolutly unnecessary change, I just thought I could suggest a thing...