During my engine swap project I had to get some flange nuts from the local Ace Hardware. The Mazda 8M nut requires a 12mm socket, but the same nuts available locally require a 13mm socket. Same thing with the 10M nuts; a 1mm larger size socket or wrench is required. Anybody know WHY? Of course, you can buy the OEM nuts for a mere $2.50 each, but who in their right mind would pay that for a stinking nut!!