WOW - That 928 with the white interior looks fantastic. I did the same to a 911. Striped out the interior carpet & padding and then rolled on a thick truck bed liner. Sealed and protected the metal real well and also provided some sound deadoning. When everyone saw it, they all asked "who's going to do your interior?" I ended up having leather on the doors and lightweight carpet installed. Looks great, I think
Now, with that said, if I had to do it all over again.....I would do the white painted interior, in FLAT. It will take a lot more work and sanding to make it look smooth (paint vs bedliner). However, white will be cooler and flat paint will make touch ups just a spray can away. Gloss will show every scratch (especially black) and touch ups would definitely show. I'm on your side - weight is the enemy and must be eliminated. I have to resist the urge for my 928 "driver" to gut everything! I'll leave that to my 911. I will build another 911 some day and do a painted interior and a digital race "pack" type guage cluster. Eliminate evrything else and get well under 2500 lbs. Then shove a V8 in to really upset the purists
Do IT! You have my vote.