Is that a well-defined thing? How is one supposed to know whether the FooBar WomBat 20 is the same vehicle or not as the FooBar WomBat 20i? Do auto industry ins

Is that a well-defined thing? How is one supposed to know whether the FooBar WomBat 20 is the same vehicle or not as the FooBar WomBat 20i? Do auto industry insiders have a clear concept of this?