swiftech blockes are anodized inside and out which prevents the chemical reactions of copper and aluminum being in water together also.. anodizing helps that corrosion alot.
and kibbler swiftech blocks will beat most copper blocks
just because its aluminum (which the part thats touching the CPU isnt even aluminum its copper) dont mean the WB sucks.. swiftech makes very good blocks. and its sorta pointless to cool the water after it goes through the WB you want it to be the coolest when it goes there. so put the rad be4 the waterblock and after the pump.
and swiftech blocks love high flow so get the highest flow pump you can afford (quality one tho) like eheim hydrothruster little giant ETC. (not a cheap powerhead of some sort or $20 pump)
and after your watercooled ill bet you $1,000 you will be curious to see what it can do
lol (overclocking wise)