3" or 2.5" exhaust (pics)

do you have a welder? personally id run 3". if you ru nan X pipe it should be the same diameter as the collector, neck it down after the x junction. if you have a mig, the 45* pipes that come out of the X, pie cut the side of them and squeeze it down to 2.5" and weld it up, or just use some reducers.