addco confusion/where to order

[pwmin]

after reading through the addco posts, i am still confused. if i order the 474u kit, do i still need to get the 612B or 612D part for the middle bracket? http://www.addco.net/install.shtml (in the yellow boxes towards the bottom of the page)

 

edit: also, where is the best place to order? keystone wants 135 plus 5 plus freight cause its a special order. thats ridiculous