are you trying to say that nissan engineers selected exactly the right balance of cost and performance for you tastes? have you modified anything on your car at all? if the answer is yes, you are being somewhat hipocritical?
The answer is that obviously a lot of things we do to our cars, are because we aren't using them exactly as nissan had intended (the stock product).
I have a large well known brand radiator, with a 16inch fan on my GTR. I haven't had water temp problems, although I took it very easy on the track. I would therefore not be 100% in recommending it to others. What I will mention however, is that as far as I can tell, when at speed the engine doesn't really need a fan. Unless you are 100% on throttle for relatively large stretches (track) or if you are stationary the great majority of your driving (traffic), of which I frequent neither .