Not quite this easy, if only!
Had to fab custom mounting brackets and weld them to the floor. Then drill holes through the floor and drop bolts through the floor of the car and bolt them in from underneath from the sheet metal pan(there's some extra metal welded in for added security).
For the heated and cooled seats, in the STS the factory setup works through the climate control head unit. It sends a serial data message to the control module in the seat. There's no simple way to fake that, so the heating/cooling elements are wired directly to switches, each with it's own power/ground. You don't have the ability to control fan speed, or temperature of the heaters, but they work.
Seats will run about a grand for fronts and rears... if you manage to find a set.