The
interior panels of the MX-3 are made of a molded fiberboard covered in a
vinyl/foam composite padding and a cloth and vinyl covering.
Other people have re-covered theirs also, so
I won't spend too much time here going into detail.
Basically,
you peel the old cloth insert off of
the vinyl/foam backing VERY carefully. You want the backing to remain intact
and attached to the fiberboard. You
then cut to size and glue your fabric
using a suitable contact adhesive. I used 3M Spray 77 
because
it has a 20 minute movement allowance.
The Fabric I used is the same as the fabric
use
d
in my new seat covers - "Sunbrella", which is meant for use on patio
furniture. It is very tough stuff.
Instructions for removing and installing the door panels are on page 65 of the body section of the shop manual.
Installation
(like everything else) is the
reverse of the removal process.