@Noisy Crow go back and check out the install pics on page 1 from a member here (2010 5MT) and you will see that he re-used his "stock" vertical bolt, but had to change the horizontal.
My understanding is the horizontal is M12x70 but the threads are not the same as the mazda (ie, coarse vs fine)
I was planning to hit up Brafasco after I got my mount to get a quality bolt - it's easy to take the mount into the shop and get one that fits...