Yea it can be done , you will need to fit the pads , control unit under the passenger seat , wiring looms and switches . The car will need to be coded then to activate the CAN bus so the car knows that there fitted . There was a thread about it a while back .
I wouldn't bother if I were you. They are very slow to warm up and do not stay on for long. Worse, those in my '99 W210 estate are incredibly unreliable and expensive to replace. The first failed within 12 months, and they go at roughly one a year. At £400 for each pad I gave up years ago. Buy an Audi if you want real heated seats.