I have to replace the exhaust manifold on my Cherokee and was curious if I should just go with a stock one from Chrysler or upgrade to the one from Banks or Omix.

i would just do a stock one, the upgraded aftermarket ones are usually a bit harder to install cause of how they route the tubing yet make very little difference in performance from what I hear. They are also very expensive. I went with a Dorman replacment when I did mine, no problems yet and it's been about a year.

why does it need replaced?

Be sure to check your motor and trans mounts before replacing manifold I put a new one on and 6 months later mine cracked again turned out motor and trans mounts were wore out, good luck

For an aftermarket one the Banks is a top rated one for sure and does have an excellent warranty. It fits very well also without issue in most all applications.

Just installed an apn header from amazon to replace my cracked one. No noticable difference over stock.

It's cracked and won't pass emissions in Utha

Utah

if you have the time you can get the crack welded for pennies on the dollar compared to a new one. and you know it'll go back together like factory.

I'm tempted to do that.

i pulled mine and had a friend take care of it. not the orig plan but worked out anyhow. I also changed the offending mounts prior or during said exhaust manifold work.