A set of headers comes with the down pipe and they run about 600, A good down pipe is about 200 alone. There are some guys selling cheaper downpipes (75-100) but they are no more than crushed pipes with poor welds.
Notice the bottom pics, stock is just over 2" not 2 3/4"
So you could go with ported exhaust mannys and a 3" down pipe but you would be looking at close to $400, for a few hundred more you could have headers?
So far I would have to say headers have been my best performance mod.