I had a devil of a time finding a 5/16" bit to fit the coolant drain plugs. I eventually took a piece of 5/16" square stock and welded it into an extra socket to make the tool.
I also have the Oil Guard by-pass. I like it, but the cost of the filters is ridiculous. You can tell they have a monopoly on the filter element!! I am running this bypass with an Amsoil EaO99 primary filter. The oil stayed a honey color right up to the 5K mark. At 10K I will send in a sample to see if it's time to change it yet or not.
BTW, I do not send my samples to Oil Guard. I have heard some bad things about how they do the analysis.