[pogodzib]

Moving the pumps out side of the tank should help some with your temp issues, but may not pull the temps down enough. Mag pumps are bad for heat, but good for reliability. You wouldn't want to drill your overflow box because with the volume of water that you're talking about, the overflow box piping wouldn't be able to handle it. A wavemaker isn't ideal for pumps that size. If you want to stick with those pumps and want to get them outside of your tank, look into building a closed loop system. You can build them so that the piping goes over the back of the tank so you wouldn't need to drill it. Another option would be to buy a chiller, but that is expensive for a tank that size, esp. if you can get by without it if you rework your current setup.