I tried Corbeau and one other seat oriented lumbar product. I threw them away. This one works, its inexpensive and it actually holds pressure.
Amazon.com: Embrace Air Portable Backrest Inflatable Support Cushion: Health & Personal Care
Four panels of carbon fiber seat/back panels and wiring and controls was about 100 dollars. I don't see the vendor I used but here is the idea.
SIL Universal Carbon Fiber Dual Temp Heated Seat Heater Installation Kit - Automotive - Seat Covers - Universal Fit Seat Covers
I put the heaters under the Kirkey fabric and then use the foam to keep the aluminum from dissipating the heat. They work just fine.