Does anyone know exactly what it takes to add seat warmers to an pre-facelift a4.

 

An order from HeatedSeatKits.com - The Future is Warm. Retrofitting them requires a lot of dash disassembly to install the seat heater sub-harnesses (which you need to source). I think Audiworld or Audizine had a thread where someone had done the job. It wasn't a small job.