I have looked around on the forums for a bit now and hadn't found any clear answers so tried it out myself and wanted to let everyone know that this works.
If you are looking for a cabin air filter for you wgnc34 series 2 I found that the filter from the Nissan Pathfinder R50 or Infiniti QX4 works. Below is a installation guide and comparison of filters
Open your glove box, squeeze the sides in to get it around the edges, disconnect the little white plastic clip at the back attacked to a string.
There are 4 screws on top and two on either side of them glove box
Remove the glove box from vehicle
Remove little metal clip on the bottom and pull filters out.
Here are 3 Side by side comparisons of old filter and pathfinder filter. As you can see they are the same size, except slightly thinner
Fits in and seals perfectly
For those in Canada you can pick this filter up from your local Canadian tire. Please post in the reply what the part numbers are for your country (FRAM FILTER CF10555)
I'm sure this is the same for R34 skylines as well