Gearbox and transmission are different terms for the same thing. A CVT is a type of transmission, just like a Manual and standard auto are types of transmissions. the only additional item you need to be aware of on a RWD car is the differential, which is at the rear, it also has oil that needs to be changed at specific intervals.
I don't think the CVT is all that bad, there are a couple of horror stories, new fluid is insanely expensive and nissan are the only people who make it. The biggest issue is finding a mechanic who has a clue about them.
Here is an ebay link for the fluid.. not sure how many tins you will need for a full flush, probably 3 at a guess. That said, there was a guy selling 1 tin on ebay for about $350 recently..
http://www.ebay.com.au/itm/Nissan-Skyline-V35-350-GT-8-Transmission-oil-KTF-OIL-/220879380863?pt=AU_Car_Parts_Accessories&hash=item336d6fe17f