found out about this last year and I posted it in one of skyline club's forum. They are made in China apparently. Better to deal direct with Japan aftermarket companies.
Contents: N1 oil pump
Description of item: N1 oil pump from gtr34. Can fit into rb26 and rb25
Condition of item: used, good condition
Price: RM1200 excluding shipping
Location: Ampang, KL
Collection method...
I'm driving waja for 8 yrs and there is some noise coming out from top right corner. I'm suspecting worn ball joint, suspension bush or strut top mounting.