^You'll have to get Aspire or someone else in here to forward that question abotu the pump. I don't think you'll have a problem with it, but don't quote me on that. But as far as the 120 Rad; depending on your CPU temps, the fluid only being in there for a short period of time (120mm size rad) won't exactly be large enough to provide sufficient cooling.
It also depends on where the radiator is mounted. If it's mounted in a little 'cubby-hole', if you will, it may be recirculating the hot air expelled by the radiator and thus adversely effecting the cooling benefit of the radiator. If the radiator is mounted out in the open air, it will run cooler and hot air will be expelled more efficiently.
Personally, if I am doing testing on the computer, I stick a box fan right in front of the computer to help get rid of the hot air expelled by the case and the radiator, and to blow cooler air onto the components.