the shape of the blades is different, and i think the number of blades too? i know the NA fan doesn't clear the water inlet on the engine on the TT (i tried when i converted) but I never tried to use the TT fan on an NA... i don't see why you wouldn't be able to use the TT on the NA though... anyone?
If you keep the NA Radiator I think you are going to have to make some custom hoses because where the coolant enters the engine is different on the TT and the NA. So I think it would be best just to get a new radiator too. I never tried putting a TT fan on my NA I tried giving my fan to a buddy with a TT as I have the electric fans. But the TT blades are different although I dont recall how. Also I think our fan stick in closer to the engine and the TT fan stick out a little more. Its a significant enough difference to where the NA wouldnt fit the TT as far as vice versa, im not sure I havent tried.