You'll need a 14mm wrench, and some M10 or M12 washers. I just bought my washers at lowes for $.80 a bag. You may also need another 14 wrench or ratchet to hold the bolt still while you wrench at the nut, otherwise the whole thing might just spin in its hole.
I just reinstalled my hawgzawst last night with 2 washers, sounds like a ferrari with these equal length headers! (almost )
May have to tone it down to a stage 1 hawgzawst...