OEM exhaust removal clarification

FromG2Z

Been reading this:

DIY: Stock Catback Exhaust Removal

Guys... have a question on this DIY. As I prepare to do this on my own this weekend.

1) The black rubber brackets that support the muffler and mid sections have to be slid off the existing muffler hangars, correct? Hence the reason for some "lube".... so they have to be reused for any new muffler to be installed?

2) So does that mean the hangars on ANY aftermarket muffler (I ordered Invidia Gemini) must be located in the same relative location as the existing muffler so as to use the existing mounting holes on the car frame?

3) This was stated in Step 7: The Y-Pipe has no such supports so simply remove the 4 bolts loosened before in Step 2 and it should come right off like thisThen what are the 2 black plastic looking pieces on either side of the Y pipe? Are those O2 sensors? Nothing was stated in the DIY for removing anything other than the bolts holding the Y pipe to the cat...

please clarify the above 3 points... thanks!

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2012 5.0 GT Prem, Kona Blue, 6MT, HID, Brembo, 3.73 -- Ordered: 9/20/11, Born on: 10/20/11, Delivered 11/15/11"Marilyn" GT500 mufflers/flaps, MGW shifter, FRPP K springs, BMR panhard bar, Boss coil covers, 3DC spoiler, Llumar Tint (35% and 20%), 3M ClearBra