Official datasheet for "E2" does not exist.
The only difference is that "E" models are shipped with 6 cooper ports and "E2" models have 4 10Gbit cooper ports. And if required, that could be extended with a riser (optional PCIe fiber card).
Fiber card could be 10Gbit Short Range (SR) or 10Gbit Long Range (LR). Both Fiber card have 4 connectors and includes SFPs.
All other parameters for E and E2 - are the same.