I agree with HowardJ - the results from the kit are excellent. The hardest part was going at my headlights with sandpaper and making them have the clarity of milk jugs (the first step of the process). But take heart, they do come out looking like new in the end.

A word of warning - plan on investing several hours worth of work if you want a perfect finish. Now I just use Plastx every few weeks to keep them shiny and clear.

I got the kit I used at Autozone for about $20.