in addition to distilled water u need to use some sort of anti growth agent. like WaterWetter, Zerex racing fluid, etc.. these are for stopping growth of algae or some sort of life, having all copper just prevents corrosion of mixing copper and aluminum.
and no not all parts of your system are copper. the Swiftech MCW5000A uses a copper base but the top is made out of aluminum which has been anodized. the use of waterwetter or zerex helps prevent the corrosion but its not always a gaurantee.
you should go with 1/2" ID tubing. u need to buy a little adapter for quick connects that allows the 1/2" ID tubing to fit into the 1/2" OD quick connects on the block.
http://www.cooltechnica.com/Merchant...egory_Code=SWS
you should mount the radiator in front of you case and suck air through the radiator. but u can also use a push/pull setup if you want to. what that is, is two fans on the radiator. one for sucking air through and one for blowing air through.