A number of manufacturers have squeezed electric drive trains into existing chassis. A number of these attempts were reasonable in their approach due to chassis designs that had built in capabilities to allow gas, electric, hybrid and hydrogen based drive trains from the same platform. Mercedes B-Class and Smart Electric Drive platforms were designed with multiple drive unit options, and room under the cabin floor for low/flat battery placement.
The problem comes when trying to compete head on with Tesla in the premium performance segment, something Porsche needs to do within the next 5 years, or get used to declining market share. They've chosen to compete head on. Good luck.
My wife promised to buy me a Porsche for my 50th birthday, but we changed our minds after driving our little Smart Electric for a few years, it just became more obvious how much better a pure EV is compared to gas. So she traded aware her Mercedes SUV for a Tesla. The Tesla is awesome. My Porsche owning friend is likely to get a Tesla when the Model 3 comes out. It's lights out for pure-gas powered cars in the premium segment, it's only a matter of time.