If you are very mechanically inclined, and have all the tools/parts, you should be able to do it in less than a weekend.. if not.. well... longer.
did you: install your own gears? your own HCI? Can you adjust your own timing?? Have you changed your own clutch?? Have you done your brakes?? Have you done your exaust on jack stands in your own driveway??Have you done your pullies and balancer??
If you answered yes to all or most, then you are mechanically inclined, if not, well....longer.. if you answered no to most.. get help from someone who has.. that will help alot.
are you getting a kit with an intercooler?? add 4 hours minimum.
That is a extremely broad question because of how many different applications there are. Some mount on the drivers side which means battery relocation among other things, but I will assume what you are talking about is a basic passenger side kit. Count on not only doing the physical installation of the supercharger (brackets, piping, belts, etc.) but also figure in the time it will take to upgrade your fuel system (in tank pumps, in-line pumps (t-rex - those take a little while) injectors, fuel pressure regulator or FMU, etc.) I would say you could get one installed anywhere from 6 hours (my buddy and me with his Kenne Bell, more or less an upper intake swap) to about 10 or twelve hours. Maypo hit it on the head pretty well, about a weekend if you have any mechanical inclination.
I have installed my cat-back, MGW shifter, and 4.10 gears (with trac loc rebuild). So I am no master wrench by any means, but I survived the gears well. So I got dat going for me . . . eh . . . which is nice.