Q&A

 Technician

Unfortunately, even the aftermarket headers can break so use a brand you trust, with a good (hopefully lifetime) warranty (Edelbrock?, Banks?, Thorley?, JBA?). I'm not sure JB Weld will hold, I'm told they break where the collector is welded to the header pipes. If you have access to a small 110 volt welder, that might worth a shot. I'm afraid I haven't had to replace the one on my '91 yet so I can't tell you which brands to avoid. Unfortunately when it comes to headers in general, cheap is not usually a longlasting solution. I can tell you there's a million Jeeps out there so I bet you'd be able to find a used manifold from a pick-n-pull or classifieds. Supposedly the factory manifold for the 2000+ Jeeps is better than the earlier designs because it is a cast design.
For my Jeep and Toyota truck parts I've used 4wheelparts and Quadratec with good luck.

 Master

I would suggest replacing the exhaust manifold with the stock replacement manifold available from the dealer for $186.62 you will need the exhaust manifold gasket and the donut gasket that goes between the manifold and pipe, Trying to install a header pipe is a big job and should be done by an expert but changing a exhaust manifold is a job you and your son can do.