I don't think it's strange nor unbelievable that it only shares 7% part count. But the number or parts that started as elise parts and then went under the knife for changes to suite the various needs, i think is substantial. It started as a lotus, and due to various marketing and engineering requirements, lots had to change.
The point is that besides the drive-train (which is a huge and big difference i agree) they're very closerly related... and citing that the only 7% of parts are common as a statement of how fundamentally the cars are different is a bit hilarious. I'll make a simplistic statement... but i think it is largely obvious that if the car was so different, then there would be no reason for lotus to be building it. 7% of the components in a lotus are pulled from econo box cars. who cares!?!
I must say, people spending all the time trying to differentiate them is funny. I totally understand from a marketing/sales perspective. But in an honest and open discussion about the nature and foundations of the cars, it rings rather obvious of elitism or ignorance, or semantics... two of the three are a bit sad. Part of the reason for the success of the tesla is because of the foundation of the lotus' lightweight, fairly simple, and efficient design. I think the tesla engineers have made very good use of that... they took it and did something unique and very fun. I'm very envious of that drivetrain.