High Flow Catalytic Converters(Help)

[03TundraTRD]

I just installed my Spin Tech muffler and now I want to replace both cat converter with Hi-Flow ones from car-sound.com with new piping from the #1 cat back to the muflfer, but I see that the #1 catalytic is VERY close to the header pipe. So, I was wondering if I remove the #1 catalytic and put the Hi-Flow catalytic further back(about 3 inches) to make it fit will it affect the o2 readings or am I going to be ok.

[DevinSixtySeven]

word on the streets is that the stock cats really aren't a problem as far as flow...not really any need to replace the stock cat(s) unless you f'd them up

-sean