Got a New Oil Filter Stud from Nissan today, one from a RB30, when in prefect.
For those wanting to know, car is track only, running a oil cooler which will do much better then the oil to water cooler this way I've removed plenty of the water lines and got more room.
As for you GT-T1998, you can basically do the same thing, the block on the RB25Neo is pretty much the same, the thread will be exact same, so just go to nissan and ask for a Oil Filter Stud from a RB30, I can post part number up later, cost me $19, Will be worth it.