Distilled water beats any coolant and is cheaper to replace when flushtime comes around,
I'd also go for a better Rad, the EX series are the same size as the Rs but cool way better, almost as well as the Rx series,
and if overclocking I'd suggest an additional 240 rad to go with it
and if the rad is in the roof, then have it blowing air out of the case,
front,side,bottom intakes, rear and top exhaust, rule of thumb for fans and rads
Moto