torquing spark plugs is not like torquing a regular bolt. USUALLY, it finger tight + 1/8 to a 1/4 turn, depending if there is a sealing washer used or a taper seat. i believe the Mazda2 head uses a taper seat for the plugs, so it would be finger tight + 1/8 turn. check with the plug manufacturer for specifics. (should be printed on the box)