To install most of parts out there, you need to put it in SLRR's main directory/parts.
To stance cars, use VStanced suspension. It' in DL section.
Also, check this out. Some people will probably tell you to read this.
If you got any questions, feel free to ask here.
And welcome to VStanced!
PS: W.I.P. Mods section is for mods in work-in-progress state 😉