Not sure about the freedoms but if you get the Louie's with 2.5 in baffles you will have to get them tuned or they will discolor.

 

Used to live down the street from a friend who ran the Rush on a stock header with the catalyst still in it and it sounded awesome...I could always tell when he was heading out because of how good it sounded. I cant speak to the sound with an after market header though.