Honduh@Love

i got a high flow cat off ebay and it was to short to reach my header (dc sport 4-2-1 1 piece) and i have greddy sp2 cat back. the high flo cat wouldnt reach so i got a shop to weld a new flange on it but i dont think itll bolt up cuz the flange isnt the same they just put one on that reached the header and the holes dont line uup, plus due to tthe "fatter design of a cat than a test pipe, my skunk2 short shifter hits my cat constantly. does anyone have an idea of what i can do and if i should go with the test pipe? ive herd you can make one yourself by welding flanges onto a piece of pipe. is that alright to do? plz help me out ive searched and got one result.