Unfortunately that looks like sun bleaching. Do you leave your top open in the sun a lot?
It's really a cosmetic thing. You could tape/tarp up the top and apply some nice even sprays of black on it and fix it right up.
Katskin is your best bet for the custom seats. For the wheels, I would just have a local shop powder coat them to a darker/different color. Will totally change the appearance and will be MUCH cheaper than a new set of 5.