There is no mention of GTST's in the first post, ponyboy is looking at buying a 1996 R33 GTR VSPEC.
I'm very aware series 2 headlights on GTST's are different than series 1, I had a series 2 GTST ten years ago...
The zenon headlights on R33 GTR's first appeared in 1997, but are more common on 1998 models which are known as series 3's.
My car is a series 1 (95 model), I replaced the standard headlights with the zenons about 4 years ago. To fit them I removed the front bar, removed the original headlights, and bolted the zenons straight on. The only difference is the plug on the zenons has a small tab on both sides which stopped it from connecting to the original headlight loom. So out came the file and 5 minutes later the zenons were plugged in and working a treat.
In saying this the zenons aren't cheap. Expect to pay around $1400 EACH from Nissan...
This is what the zenons look like on my car....
Hope that helps....