On my custom true dual exhaust the wye was eliminated and the cross over was in the dual in dual out muffler. The installer went with the stock tailpipe size to keep from losing any low end power. I am not very good at noticing slight changes, but I have not been able to feel either a power gain nor a low end loss.
A good installer is worth his weight in gold.
OkieScot
A good installer is worth his weight in gold.
OkieScot