There's nearly 500 cars in the game. These engine swaps really transform some cars, effectively making them a totally different car.
For instance, Miata vs LS swapped Miata.
In a tuned lobby, every car is special. I never felt that my car was not special simply because someone else has one. The tune alone makes it special. The livery makes it special.
There is literally enough personalization options for every person to have a unique version of every car... For this to become "not special" seems a bit extreme.
Of course, the novelty of this shines a light on it that wouldn't be there if it had not been so restricted from the start, but still. I bet no one has a Hellcat Challenger like MY Challenger, unless they grabbed my Style and happen to have the exact same parts and tune on it.