Yep, Duncan converted his s1 to manual himself, but if you're talking about GTR seats as well, you might be thinking of my car. I bought mine because it was already converted to manual, and a factory RS-Four S was around $28k at that time (October 2005) - that was way over my budget!
Seats from an R32 or R33 do bolt in, Jason. Apparently R34 is slightly different, but I'm not sure if it's the GT/GTt or the GT-R that differs. And yeah, they are heaps lower, even compared with the factory (adjustable) Stagea seats set at their lowest setting. I've also had the rear seats trimmed to match, and the door card centres trimmed as well, but don't have photos of these yet (I've been lazy on that front).
Example:
In the car:
Mearcat clock-replacement pod housing with Defi 60mm BF Boost meter:
Home-fabricated meter panel with Defi 52mm Exhaust Temp, Oil Temp and Oil Pressure meters (from left to right). Then there's the Alpine CD/MP3 stereo under those, the Defi meter controller at the bottom, and since then I've also installed a GReddy Profec B Spec-II EBC which sits on top of the Defi controller: