Here is one of my G20:
This setup has about two feet of IC piping, all 2.5". The pump is mounted on the trans driver side mount and water lines run through the intake hole by the fender. That was a quick throw together from spare parts, but was super effective with a T28. I daily drove that setup 240 miles a day mixed driving and running 10PSI. I had no water reservoir on this setup. The cooler was behind front bumper and between the lines/cooler/IC it held quite a bit of water.
Here are a couple of my NX:
In the NX, the turbo feeds directly into the IC and there is about 12" of total IC piping between the IC and TB. Hard to beat that! This setup has the pump and a reservoir in the hatch and 1/2" lines running to the engine bay. I wanted to be able to run ice in the system on track events and only keep the reservoir half full typically. It is a fuel tank so it has foam baffling that keeps the water from sloshing around.
Brent