Bolt kits.

My vote is for the hex. Personally I don't have all of the Allen sockets for torquing and such. Also when you paint if you paint the Allen will fill up with paint LOL also personally to me the hex just seems to look correct. Again that's just me and my taste. Also you know me Ultra budget-minded like I said wire wheel, and likely just be up at Ace Hardware getting the few that I needed.. also if you're going to ever think about some headers? They will need their own special bolts.