I'm sure this has been asked before, but I'm just feeling lazy right now

Since I'm gonna be new into this watercooling bit, I've got the opportunity now to easily (or not so easily?) decide on getting a setup with 3/8ths inch fittings or 1/2 inch fittings. Just in case, I'm planning on getting a kit from cooltechnica - these guys reputable? Will I see that much of a performance increase to warrant $20 extra? Being a college student, $20 is
a lot of money!

Input is much appreciated!
-Jerry