i ve noticed you can get the seat heater pads seperately. i spent some time and these are the cheapest ones, of an 06 mazda 6



GAC9-88-121 heater pad

GAC9-88-122 heater pad

GP7A-88-1H4 harness

GJ6A-66-420-02 switch



total at mazda list is like $115, switch is like $40, harness prolly isnt needed, i think these just need power and ground