I just refilled mine through the resivoir. Just try to burp it when you are done and make sure you get all the air pcokets out of it. Pretty straight forward and easy to do.
Chris
im pretty sure you might be tired of answering this but im still new to having a supercharged car. I've changed radiators plenty of times but never a heat exchanger, by the looks of it, seems pretty simple. Just disconnecting the hose on the HE will drain all the fluid? and could you describe what burping means, not really to sure how to do that or maybe i do just probably use a different term than burping. thanks