The system requirements depend heavily on the version of Matlab you are using. Consult the accompanying Installation Guide or check The Mathworks. You may expect that SPACAR will run on any Microsoft 32-bit Windows PC on which Matlab/Simulink are running.
Only the base systems of Matlab and Simulink are required to run SPACAR, but additional toolboxes like the Control System Toolbox may be helpful to develop and analyse control systems.
The installation of SPACAR uses less than a few MByte extra disk space.