I would... Go GTR fluid, helps with brake fade.
I THINK Nissan recommends brake fluid flush every 30k or some BS because it absorbs water from the air which does something and it makes the pads not last as long, and yada yada...
Just make sure you don't get raped for a liter of fluid, The Nismo Shop (West Covina Nissan sells it for $30
Nissan Factory OEM GT-R Special DOT 4 Brake Fluid KN9U0-40001P - Nissan R35 GT-R)