Has anybody added lumbar support in the passenger seat? I have a SR5, which only comes with power lumbar for the driver's seat. My wife is suffering from lower back pain during longer trips (2+ hours). She's tried adjusting her seat, but it can only adjust so much. She also tried one of those lumbar pillow things, but states it doesn't help because it pushes the lower back away from the seat, but leaves the upper back in an unnatural position.

A quick Google search shows that some people added a manual inflating lumbar cushion behind the upholstery and having a hose with hand pump to increase/decrease the lumbar support. Has anybody tried this on a 5th gen? Any other recommendations are welcome.

Swap in GX460 seats?

Look into Rostra's kit; I used their Toyota specific seat heater kit and everything went (fairly) easily. For disassembling the seat/cover find someone with small agile hands

Had this exact issue with my fiancee. We ended up trying a bunch of different pillows but most just pushed her back out too far.

We found this pillow to work decently.
Amazon.com: CONFORMAX Airmax Car Seat-Back Gel Cushion: Automotive

For me the pillow route works best. But it's true that basically every pillow you get is too thick and pushes your lower back out too far. I ended up buying a cheap memory foam type pillow at a discount store. Then I sliced the thing in half on the flat axis. Like separating two pancakes. It was a bit tricky to cut but that left it the perfect thickness for comfortable support.

Sorry to resurrect an old thread but I would love to do this; Has anyone done this and is pretty straightforward plug and play?