maybe i can help. the oem dual radiator can support the high number. yet when it comes to air in the system. first make sure the system you have in the car is seal such as air is not being pulled from anywhere else.
second it takes a good while to make sure the system is good.. on my gsr it took me 30 mintes to get the bubbles out. i left the rad cap off and opened the valve.
if the t-stat is good the if just need a good bubble check.

if ur going to buy a oem one just get a after market one because its cheaper unless u have a discount