Used the Meguiar's PlastX yesterday on the headlights, foglights, and taillights, with varying results.

Headlights and fog weren't bad to begin with. The PlastX seems VERY similar to the ScratchX product. After 20 minutes of hand polishing on each headlight (about 5 songs' worth via the surround-sound system in the garage), they looked slightly clearer. Probably would need the sanding/polisher approach to get them closer to crystal clear, with fewer tiny pits. The fog light covers, down low on the front, took about two songs each.

But the taillights were a different story. Again, about 5 songs each. They had, if you looked closely, numerous scratches from someone's previous paint polishing attempts. With the PlastX polishing almost all the scratches came out, and the surfaces of the lens are much shinier. My guess is that the taillights are made of a much softer plastic, and so they polish-up much easier than the headlights.

Didn't do the side markers, but should take a closer look at them today.