I wouldn't bother with a bowl change on the JE, myself. Although it will fit, I think the "deficiencies" they talk of on the JE relate to intake size, volume, etc. Haven't noticed these "deficiencies" much myself, comparing performance of my JE with my JG or JC. It's just a little different, but uses mostly the same parts! What I see as an advantage is the impeller is MUCH closer to the water, and water from the intake has a far less path to travel to get to it. Plus one less leak point. But I ain't racing it either.
JMO. Throw on a diverter and a loader and I think the JE will surprise you on it's own!
Ray