Does any one know if the heated seating elements from another Audi or VW car will be compatible with the A4 B5 switches and loom?

The elements are cheaper than the complete seat.

For example.
NEW GENUINE AUDI A3 HEATED SEAT ELEMENT - 8P0 963 557 B | eBay UK

AUDI Q7 FRONT HEATED SEAT BASE ELEMENT - 4L0963555E | eBay UK