It doesnt make a difference its just the muffler. There is no need to replace the factory piping unless you need to go bigger. When companies sell the full exhaust the same size, its a scam.
None whatsoever. Remember its my wifes daily driver so I wouldve heard about it by now. Not be a douche but comparing magnaflow/flowmaster to borla or corsa is apples to oranges. Theres a reason behind the price difference.
