I've used the Back to Black on my DD in the past but one thing i noticed is if you stop using it the fading seems to come back worse. It may just look worse since you've had it nice and dark, but done every wash it does do nicely.
For flares i would give them a coat of paint. Ive used the bumper coating from Advance auto several times. Painted all the plastic flares and bumpers on two older Nissan Frontiers with a buddy several years ago and they held up good. Also done the flares on my yj, just get them really clean then a couple light coats getting heavier each coat. I actually bought the bumper coating for my jeep at Walmart and it did just as well.