More customization to families on Car Designer!

Hey!
I was modelling my car here, and noticed that, while a given base model has a hatchback and sedan version, I couldn't "port" all the fixtures I've already placed on one model to another (which seems to be the same "model")
I'd understand if we lost the tailights and rear fixtures, but why do we have to start from the scratch on the front and sides? They're basically the same thing. Even if it's stretched and modified, couldn't the same faces be used in both models?
Also, I couldn't add fixtures or stuff to "more expensive" version of the same car. I made a basic, inexpensive version of it, then I wanted to make a sport version of the very same car, add some spoilers, lips, fog lights etc, and I noticed it was blocked! I thought about creating another car with the very same name, but I'd need to port all the fixtures from the "basic" model, so it would be convincing, and gave up on the idea
And last, but not least, why not a list with the placed fixtures, so you can click and select it? I like to place one fixture on top of another, to make a composition and look good, but sometimes I place it incorrectly, and have to move everything out of place so I can select a single fixture. It's not very cool, if we had a list of fixtures that we've already placed and could select one individually, would make it easier.
I was modelling my car here, and noticed that, while a given base model has a hatchback and sedan version, I couldn't "port" all the fixtures I've already placed on one model to another (which seems to be the same "model")
I'd understand if we lost the tailights and rear fixtures, but why do we have to start from the scratch on the front and sides? They're basically the same thing. Even if it's stretched and modified, couldn't the same faces be used in both models?
Also, I couldn't add fixtures or stuff to "more expensive" version of the same car. I made a basic, inexpensive version of it, then I wanted to make a sport version of the very same car, add some spoilers, lips, fog lights etc, and I noticed it was blocked! I thought about creating another car with the very same name, but I'd need to port all the fixtures from the "basic" model, so it would be convincing, and gave up on the idea
And last, but not least, why not a list with the placed fixtures, so you can click and select it? I like to place one fixture on top of another, to make a composition and look good, but sometimes I place it incorrectly, and have to move everything out of place so I can select a single fixture. It's not very cool, if we had a list of fixtures that we've already placed and could select one individually, would make it easier.