Exhaust q?

OK. I'm working on ways to get better power from my 4.0 and doing some research... One question though:
Where do I find a better-flowing replacement for the S-shaped tube running from the stock manifold to the cat? I can find all sorts of cat-back systems and I hear the stock manifold is good (if it isn't cracked) but what about this down tube with the huge kink in it? Links?
Thanks...

you could cut the kink out and weld in an unkinked piece.

there are a few companies that make the down pipe but it depends on what year you have and what header you run