I want to know if it will really make that much of a difference if i use 3/8 or 1/2 inch tubing. The water pump is uses 1/2", the resivor uses 3/8 or 1/2" it can be made either way, the radiator uses 3/8", and the waterblock is 3/8" or 1/2". So all i really need is a converter for either the water pump, or the radiator. I know if i use the larger tubing there will be lower pressure, but would there be a performance difference and if so could go give me a general estimate. Also this in inner diameter on the hose measurments.