Swapping to the g3 headlights on a g2 will probably require more fabrication that you realize. It has been done, and looks nice, but like I said. I don't know of too many shops that would be willing to do a full front end transformation like that. I would just go with the JDM 1 piece g2 headlights. If you get a good set that are clear, it is definately one of the best visual modifications that you can do for a g2 teg. Other than the JDM lights, there aren't many other options that are readily available and made specifically for a g2 teg. OBX Racing makes a headlight for them that supposedly has a black housing, much as the JDM CTR headlights are, that are made for a g2, but I've never seen these.
Below is a pic of g3 JDM ITR headlights retrofitted to a g2. Realize though that this would take a some custom fabricating on the hood, fenders, and bumper to make this fit, to what extent of customization I do not know, not to mention how they actually bolt into place because I believe that the mounting brackets are different. Anything can be done if you have the $$. OPTauto.com sells these (JDM g3) headlights in both a chrome housing and a black housing. I would personally lean towards the black housing ones, but that depends on the color of your g2.
hope this helps you some!