I know I talked to you via PM but figured I'd post this here for future reference. Short of buying all new plastic there are no awesome solutions.

The one I would go with is rattle can paint. You need stuff specifically for painting plastic. You can get it any big box store out there. Prep it, spray it with primer then paint it whatever color you want. On a previous XJ I went with desert tan on my fender flares, wipers and corner bumpers. It won't look perfect but it will be presentable.

You can use cleaning chemicals that darken the plastic back but they will need to be reapplied often, how often depends on a bunch of factors but expect it to be once a week to once a month depending on if you have a garage or not, and the quality of the product use.

The "best" solution as far as how it looks is to somehow source a set of new plastics which will probably be pretty expensive, I'm not even sure if they still make replacement flares and what not. You could always go aftermarket but again, that will be expensive. The painting option will be 40-60 dollars probably.