Hello, new to this board.. I'm looking to put a pair of Flowmaster 40s on my 2012 Impala LT. Can anyone clue me into what else I would need other than the mufflers? I know I need the 2.25" offset in/center out type but when I looked up the diagram for the exhaust system on Walker it says the inlet part is 1.875". What kind of reducers and all that stuff would I need? Your help is appreciated! Thanks!