Before you buy this, don't.  Get the 3M 39045, which has the top coat included in the kit!First, the before and after pictures are not an exaggeration.  The system will indeed produce a clear lens by following the directions.  That part of the process I would give 5 stars to.  The directions are very clear, but I would add a few items of my own, having made some mistakes.1) If possible, remove the covers from the vehicle and secure to a stable work surface!!  If not, put a triple layer of masking tape around the edges of the lens to protect everything within 1.5 inches of the cover. (Use the green 3M tape or blue if you have to, NOT the tan kind!!)  If you are inexperienced with using a pad mounted in a drill, you will have trouble holding the pad on the surface at first and you'll end up with nicks and edge marks around it.2) Use very, very light pressure on the first stage.  Let the sandpaper do the work.  This will help you keep more of the pad in contact while you control the pad's movement. Plus, it will help you avoid digging in the edges of the pad and causing very difficult-to-remove marks or burns.3) Use a slow speed at first.  The instructions give a min/max RPM recommendation, but I found the pad difficult to control when it was spinning that fast, plus it was very easy to cause burn marks.  Once I dropped the speed to slow, it became very easy.4) The first pass is what does all the yellow removal, so take your time, use up all the sanding disks (3 per lens), and wipe the lens often to see where you've missed.  If you dig into the lens a little, then concentrate on that spot more.  The second pass will not correct deep scratches, so work them out on the first round.5) The remaining steps are simply to remove the previous step's sanding marks.  Use light to medium pressure.  Wipe often.6) With the final tri-zact pad, it takes light pressure.  Be careful not to damage this pad, since there's only one in the kit.  It had no problem going the distance, but be cautious around the little nibs that stick up from the lens, etc.  Keep the pad wet, and also keep the lens wet.  The instructions say "damp", but you'll have better results with more moisture (to a point.)  Rinse the slurry off and wipe with a terry cloth often.  If you have a light handy, shine it at an angle to help see any sanding marks you've missed.7) With the sanding complete, you'll need to polish.  The sponge pad is very absorbent, but a little compound goes a long way. The first time you add compound, use the recommended dime size and work it lightly around and into the pad with your finger (drill turned off.)  Then put another dime sized drop on and place the drill on the lens lightly before turning it on.  Same as sanding, but now you're using medium to firm pressure for the first 4-5 passes.  Cover the lens in repeating passes left/right and up/down until you've been over it 4-6 times (per directions.)  Use reduced pressure for the last couple passes.  You will probably have to add compound a couple of times, but after that there will be plenty in the pad.  I only had to add it once on the second lens.  If it slings off or builds up, you've got too much on the pad (just squeeze a little out on a rag.)8) Finally, use a microfiber cloth to remove the hazy compound.You are NOT done, however, because this kit only cleans off the lens.  It does NOTHING to protect the lens! It's going to yellow again within a year if you don't protect it somehow.3M makes a protectant product, which is included in another kit - 3M 39045, which is an overall better choice than this one (the protectant and green tape are included in that kit.)You can also clear coat it with a clear gloss spray-can finish (as long as it's an exterior grade finish.)  You've already got it taped up, so mask off the area and go for it.  That will last much longer than the 3M protectant.  Don't forget to do an extra prep cleaning before spraying.That's it.  My total time was about 1 hour for two lenses on a Toyota Corolla.  Overall, I'm satisfied, but I wish I'd known about the more complete kit for just $4 more...