Should've gotten the heated seats but didn't-now what?

Don't let this happen to you! I didn't get the heated sets in my 2003
C-Coupe and now I'm sorry. They didn't seem necessary, I've never felt the need for heated seats in my other cars, but this one's different. There must be something about the construction of these seats because they really suck the heat out of my butt!

My dealer says they can't add the seat heaters, so I got some info from a local upholstery shop on adding seat heaters. The brochure warns that the heaters should not be installed in cars that have airbag sensors in the seats. Does the 2003 C-Coupe have airbag sensors in the seats? Is is possible to add the (factory) switch in the dash, or would that be the equivalent of brain surgery? Anything else I should be thinking about? Is there one after-market heater that I should look for?