I might throw 2cents into this one. I just had (literally today) my GTS exhaust installed with a similar setup. 4-into-1 w/2" at the collector, yet the GTS exhaust was 2 1/4.
Now, the bends didnt make a correct fit anyway, so I had a shop remake the pipe section (about 80% of it) in 2 1/4" mandrel bend SS, up to the header flange. The pipe just "flows" around the suspension area and looks excellent. Zero loss of flow with the mandrel pipe.
The sound is great, looks needless to say are outstanding!!!
Bob
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