Is solidworks a good software for powerfull car designs?

It depends on what you are creating. For a full assembly of a production car, SolidWorks is not a good solution as past a certain number of components it is too detailed and thus too slow for very large assemblies. Also the surfacing tools in NX and CATIA tend to be better for modelling vehicle surfaces. I use SolidWorks to design dune buggies and similar open vehicles where there aren't nearly as many components, and it works great.

I don't know to much about Solidworks, I usually work with Autodesk software (AutoCAD, Inventor, Revit). I do know that a few years ago Autodesk came up with "Autodesk Alias Automotive" a software just for modelling vehicles, might be worth a look.
Greg