i'm gonna do some work on my car, and just in case the cat. converter is cloged i want to replace it with new one. what's the best/cheap place to get one?

thanks

They're like $800. Not exactly a preventative maintenance item.

but aftermarket are like 7-8 times cheaper. or is there something "special" about the nissan one? and btw anyone know how to know if the cat. is good or not (cloged or not)?

You can get a universal cat welded on for about 100-120 at muffler shops.