Cat or no cat

[3500duramax]

I am going to put flowmaster single in dual out 50 series on my truck but i want to get rid of my converter.  I heard about something called a catalytic converter test pipe but i dont know where i could get one for my truck. does anyone know?  Also my O2 censor is right in front of my cat so i could get rid of my cat by cutting it off but its really close.  does anyone have any ideas??   Thanks