I've read a lot of these posts over the past month and just did my headlights this weekend. I have to say that this is the best thread on the subject.
Here are a couple of lessons learned from my experience:
- Like the post did ... start with 400 grit paper. If you have a lot of grit-looking then you need to start aggressive (don't worry.. there's plenty of plastic left)
- The sandpaper is great, but definitely use a (rubbing) compound. The paper will always leave cut marks and the compound on a DA will smooth out everything
- After the compound.. .use a ScratchX type polishing compound to get the smoothness and get rid of any swirls for fine marks
- Don't forget the sealer!
2005 545i SMG // Grey on Black // 19" VMR HyperBlack
2008 335i Manual // Sapphire Black on Black