Replacing the metal coolant lines ... exhaust are cracked.

A few questions.

It's a 91 MM 2.4 EFI

Can I grind then weld on these or is it pointless?
Who or where can I find another?
Does anyone know if a galant, eclipse, or other vehicle that might have used the same exhaust?

I keep replacing part after part so far ... i would prefer a used but it does not look like I am going to find a used one. I can't have it just sitting in the yard for weeks waiting for a part ... i wish someone would make easier to find parts!!!

Thanks for all the info!