Because you're so new on the turbo "thing". Do yourself a big favor, and don't worry about how you can get this part or that, if you don't even know how it generally works. MD on this site has plenty of articles on turbocharging and how it works, what's effective and what keeps your motor from dying.
I take it that due to some budget concerns, your LS is the only car you have. It would be a shame if you didn't know how things worked, which turbo to use, lines, piping, etc,... go through all these cheap parts, not do a final check on your own motor (mileage, compression test, fluids, etc) just to have it blow up..
If you don't even know what a 16g means, it's a good indication that you should not attempt to fit it on your car, or manifold (which you still don't have, or know which one to get) for that matter. Totally different company and terminology.
My recommendation is to SAVE MoNEY.. The cheap route almost always tends to be much more expensive in the long run, even if you're mechanically inclined.. I can't stress this enough.
Some of us here can help you put a RELIABLE kit together, but you will spend some cash. Converting an orginal NA car into a Turbo is not a cheap thing to do... Hell, it's expensive to modify a factory turbocharged car.