>Question here... would with the Plasticity with xnurbs modeling would be faster and easier to model a car instead of blender?

When comes to Xnurbs As the song goes, Don’t Believe the Hype. If you are already own plasticity I'm sure you will find situations that it could come handy.
I'm not familiar with plasticity´s implementation of Xnurbs but as a rhino plug-in has not been received well, here is an example.
https://discourse.mcneel.com/t/unfair-and-set-up-comparisons-by-xnurbs/137130

ps. Don't give me wrong I'm not trying to bash the developer or his tool but one thing is for sure it's not something on steroids as the Youtubers advertise it.
If I could give an advice is to understand the fundamental of surfacing no matter what software you choose to use. I think you're gonna get a lot out of this series.