I have been told that Koyo Radiators are best replacement/OEM. I'd prefer to keep as near to stock as possible. (Plastic top & bottom tanks?) What is the best source for Koyo radiator? Does anyone in Australia stock them?
1. It uses welded aluminum tanks instead of plastic tanks that are glued to the core. Much less likely to leak over time.
2. It has about a 20-30% greater coolant capacity due to using a slightly thicker (36mm) core. This results in a bigger heat sink, and the car can manage high temperatures for a longer period before overheating.
3. Fitment is OEM perfect every time.
However, I generally recommend the OEM radiator unless the owner is planning on a lot of track driving and/or has forced induction on the engine. The OEM is well made, will last for about 20 years before it leaks and of course will fit perfectly. It's more than adequate for a 3.0 engine and will suffice for an unmodified 3.2 (though the 3.2 will overheat when pushed hard- I never understood why Honda didn't make the rad bigger for the NA2- it needs it!).
If you don't plan on tracking the car much and don't have a supercharger, I would just get the OEM. Mita or amayama can supply it at a very good price. About the same as a Koyo and it will look OEM.