technically it is not a direct bolt up affair since you will need to buy a new bracket on top as the OEM bracket is not wide enough. You also will need to cut the OEM hose a bit shorter since the Koyo is thicker than OEM. The fan shroud will be closer to the front of engine as well due to the extra thickness.
The only upgrade radiator that requires no modification whatsoever is the Nismo radiator I mentioned earlier. At $218 plus shipping it's a bargain compared to the ~$400 for the Koyo radiator and bracket.