I like the look of the minimalist RS interiors and wanted to replace the stock linen carpets (impossible to keep clean).
Appbiz sells come nice carpet sets (although the standard kit does not include the carpet on the door pockets). I installed the charcoal gray felt and am very happy with the results. Some photos that may help determine which piece goes where.
To replace the carpets, you have to strip the interior. I took mine down to painted metal, removed all of the sound deadening in the back, wire brushed some surface rust in the rear seat area and coated most of the water risk areas with POR-15.
For replacement sound deadening, I put down a layer of aluminized tar paper (Peel & Seal) and covered everything in 0.25 inch neoprene before installing the carpet. Although my replacements reduce the engine and transmission noise, it is louder than it was originally. I like it but it is very subjective.
For gluing the neoprene and carpet, I used 3M #77.
After a couple years, I reinstalled the rear speaker deck for a little more sound deadening (and a little more speaker power).
I painted the rear speaker deck and quarter panels with SEM Color Coat.