Where do the tree pads go that the fuel tank sits on? I know of two, the one in front of or above the driver's feet (aft left bottom) and the opposite side but forward on the divider between the fuel tank compartment and the front trunk. But where does the third one go? When I removed the tank I just found it loose . . .

Also, has anyone used rubber rather than the felt pads which seem to hold moisture? The old ones are pretty nasty and were causing some rust.

I think the third one goes under the tank on the driver's side above where the fuel pump is on the later cars. So "across" from the one above the pedal box. Not sure on materials or sourcing outside of bugging @914Werke .

Placement

I just used this felt from Grainger

https://www.grainger.com/search/raw-materia...p;tv_optin=true

Which grade and thickness did you buy?

That makes sense and looks about right.

I caution you not to use felt or any other material that holds water or moisture as padding, or you will have your gas tank rusting from the outside to the inside where it rests on the felt or fiber pads. Use a rubber pad that won't retain water or moisture. Grainger sells self adhesive EPPM rubber sheets that you can cut into the right size and shape. I think it's either 1/8" or 3/16" thick and self adhesive on one side. I bought some a few years ago when I discovered that my gas tank had rusted on the outside where it rested against the factory felt padding, and was weeping just enough gas to create a big gas smell in the passenger cabin.

We are in the process of making up some closed cell foam pads that will be available in a few weeks.

Well said,looks like Mark @ "the house of rubber" (lol) is on to it as we speak.
I did mine with self adhesive closed cell refrigeration rubber insulation, easy .
My tank is pristine inside so no point in not doing it really,who wants leaks from outside rust !!!.
Cheers.