The Series I/II electronics will not fit in an Epic body.
Series II very similar to Series I, in fact, there is only about $200 difference in price.
Series I has a volume filter and 3-position Q swtich (0-6-9dB boost) for each pickup and a rotary pickup selector.
A Series II adds a master volume and tehe Q function is on a pot with 0-15dB range)