I think they changed plugs at around 2006, so 2008 seat plug may not plug into your car. It may only be the airbag plug that is different. As Skard said, if the plugs are different either buy new ones or cut yours off and solder yours on.
Also if your car doesnt have heated seats already, they wont plug in and work. You need all the wiring and a different set of dials where temp and fan speed are