The 1980's loop carpet in my 1968 "hotrod" has seen the end of its days. I'm replacing it with German squareweave carpet -- Chris' (endo911rs) 1967 car was the inspiration, really.

I removed the seats and started pulling up the carpet around the rear seat area, where I found horsehair material (approximately 3/8" or 10mm thickness) underneath, in fitted sections that follow the interior contours and that are glued directly to the interior sheet metal.

So... should I replace the horsehair insulation sound-deadening? Or should I use more modern materials under the square weave carpet? My car IS a hotrod, so originality is not a must for me here, especially when the insulation is out of sight under the carpet and won't be seen.

And where could I buy replacement horsehair material anyway?

Thanks in advance,
Andy