Hey Jeff K,
That was exactly where I was 2 years ago. I ended up trying both ways.
Here are the pictures I took during the project:
http://ca.pg.photos.yahoo.com/ph/mx3frik/my_photos
The pictures pretty much tells the stoires.
Album: Headlight sanding:
Sanding by hand took about 24 hours each side and even then it was distorting the beam and shifting the color hue out of the light's output.
(can be seen in picture beamwithlens.jpg. beamnaked.jpg is the output straight from the projector) Taras, however, managed to retain a perfect beam with his sanding.
Album GTS Lens Transplant:
Then I went ahead and cut out the stock headlight lens and glued GTS lenses on them. I used "Marine Goop" as glue since it cures soft. This is to avoid the lenses seperating due to acrylic GTS covers and stock lexan lenses have 3x the difference in the thermal expansion coefficient. (over here summer and winter temp diff can be as big as 70oC) The joint is covered with a black trim of paint and the entire front lens was then covered in headlight protector since the GTS covers were acrylic and thinner.
These are the lights on T-Rose's car now. As Tyler was a lot better with pics here is the final product on Tyler's gorgeous mx:
http://www.cardomain.com/ride/269675/2
cheers!
Eugene