I had that Flow Master in My Impala too, I Drove it a lil over a Year, I couldn't take the Cabin Drone anymore, I'm talking at all engine RPM though. Good Luck Starting it on a cold Morning, its like I'll aways need ear plugs. I didn't need a Rocket scientist to tell Me to go take it off. Then, put on Dual Stocks With Quad Tips.... But I can't lie, they darn sure Sound Lovely though.... That's if You're on the Outside.
It's straight pipes from the front resonator. So it still has both cats and the first resonator. Since they mentioned crown Vic's, my brother owns one and has long tube headers, cats removed, and 2 flow master 40 series and it is incomparable to mine. It makes my trep sound stock lol