Catalytic shops

Hi all, does anyone know of any reasonable priced shops in phx that will do a catalytic converter? I have to take it to a shop because the person who had it before me had it welded on. Not looking for anything crazy, just something to turn off my check engine light off. Thanks

 

Heard good things about http://www.performancemuffler.net/ I'm gonna take my truck over to them eventually to get the stupid low hanging crossover pipe re-routed

 

I like Apache Muffler a lot.. Butch is the man when it comes to exhaust.

 

I'm kinda new to the idea and work ideas, but what does replacing the converter actually do to the vehicle? I'm aware that replacing behind the converter (exhaust portion) does but no impact/no idea what the converter would do.