If you do an Intake, header, full catback, high flo cat you'll come to around that much hp. You won't see it at the wheels though.

I used to own an LS myself, as did TriDawg (we're from the same town). If you're serious about performance, I'd try and get into GSR. I'm not sure of your situation though, so here goes:

AEM Cold Air
Comptech header
Carsound High Flow Cat
Apexi World Sport (quiet, inexpensive) or Comptech Catback (pricier, noisier)

That'd be a great start. If you're concerned with smog legal, you're going to pay more for brand name parts. Getting parts CARB certified costs the companies money, so you'll be paying a bit more.