i ran this system, so i have personal experience with these exhausts. i guarantee, 100%, YOU WILL STILL BE USING A Y-PIPE. YOU DID NOT BUY A FULL CATBACK SYSTEM. two HFCs don't magically become one exhaust pipe without SOME metalwork conencting it!
here:
the amuse exhaust compares only to the Y-pipe back section of the stock exhaust.
see the y-pipe all the way in front of the exhaust?