Thanks, Im 21.
I used to not care about how loud the car was either...Im over that. Whenever something needs to be driven everyday, comfort really plays a role after awhile.
Basically, any straight through muffler will perform similarly - the same amount of gains (though its not that much...you just sound like youre a lot faster). If youre only ever going to be n/a, I suggest the super turbo, again, because its quality, cheap, quieter. Just keep in mind, that any good shop can custom make your exhuast for you, for less than what a kit will cost you.
Check out
www.kteller.com for their pipe kits (bolt-on and weld).
If I were you, Id just skip intake and header. Pick up
Maximum Boost by Corky Bell, do some research/reading and then just go w/ turbo. The LS is very boost friendly.