I presume you're doing this on your 300TD? Where do you plan on putting the switches? I just started emailing a guy yesterday about the installation he implied it should be sewn onto the seat upholestry, which I replied asking whether it'd be fine to sew it to the pad behind it. Let me know how it works out if you would.
Thanks for the suggestion I was thinking of either doing that and/or compressing the spring and leaving it that way (so it would in a way wrap around better and be firmer) but didn't want to risk screwing up my 83's seat for the moment since I already have a seat to experiment on. It'll also be my practice for taking the seat covers off.
Ok, well that is a good thing because I think I had one with real horsehair and it was always falling apart on the floor mat behind the driver, made quite a nice little mess.