I've not seen any posts on renewing hard plastic trim, only replacing pieces IF they're even available $$$$$$$$$$$$.. Unless your pieces are actually busticated (technical term), I've had great success removing the powdery, crusty layers with sandpaper then using a heat gun to restore some originality to the piece and then using vinyl colorant (seatsrestore has the best selection from what I've found.) Finish with low luster or flat clear sealant (also seatsrestore) and you have a pretty darn close to original piece to work with! You can also use the colorant/sealer trick on soft vinyl, but I've found that to be less permanent. I had to replace the A pillar trim because it was actually falling apart, but I used the colorant/sealer method on the B pillar molding and the hard plastic surrounding the quarter windows, the lower door panel and beyond. Saves lots of money too! FYI #452, (#S12156) is a PERFECT match for the dark blue color on my '81 Grand Prix. Get more than what you think you might need. And get the clear sealer too, it really helps the finish last a long, long time. Checkout fleabay. Oh yeah, it's water based! I've done almost all of the interior hard surfaces with a '4 seat kit' for way under $100 with great results. Suitable for color change with a heavier coat.