In case it helps someone else searching for this topic:
I spent months trying to figure out how to fix my uncomfortable seat. Every time I'd drive I would spend time fiddling with various combinations of the different seat adjustments trying to find the magical combination that would make this grand tourer suitable for grand touring. I also searched these forums seeing people post about leg position contributing to uncomfortable seats, but it still didn't seem reasonable for the seat to be SO uncomfortable.

Then I realized the bottom cushion seemed kind of droopy, like I was falling into it. Adding a little extra cushion on top showed what was going on: the seat was so uncomfortable because the back of the seat was hitting the back of the driver in the wrong places. The lumbar support was more like shoulder blade support, which was not where that support needed to be!

So, back to these forums, and I found posts talking about the rubber sheet under the seat splitting. Sure enough, mine was broken. After a little head scratching, I couldn't figure out a way to get any more support under the seat without going ahead with seat removal and repair.

Here's how I fixed it, with a ratcheting nylon tiedown strap I had handy. Suggestions for using patio furniture material sounded a little more proper, but this was fairly quick and easy.

I did have trouble removing that piece of molding facing the door. The doublesided tape holding it on was REALLY holding it on.

So, I hope this helps someone. Instructions for seat removal are easy to find around here. Just be sure to disconnect the battery as others warn about triggering the airbag.



Broken rubber support thing

Fixed with ratcheting nylon strap

 

That's awesome!

 

Great fix there. Never thought of using straps. Seems quick and easy.

I swapped my DIY fixed driver’s seat diaphragm with the passenger side ... just to be sure.

 

Very nice - an excellent solution, Clearly you were a furniture restorer in a previous incarnation.

 

Quick update: I probably shouldn't have pulled the straps so tight. Obviously they won't have as much give as the rubber sheet, but now when I'm sitting in the seat it feels like I'm sitting on a padded piece of plywood.

The back of the seat is so much more comfortable than before, though. All of a sudden the headrests actually come forward to touch my head! This is the old model with molded in headrests.

So, anyone deciding to go my route and use a strap to fix their seat, leave it a little loose. This is good enough for me, but if I ever have cause to take the seat out again I'm going to loosen mine.

 

I added a thick layer of foam between the diaphragm and the seat base, to give a 'lift' to to the cushion, which helped a lot.

 

Thanks for the update. It's on my 2do list.

John