So I recently bought a flowmaster cat back system off Craigslist and the guy wasn't sure if they were 40 or 50 series. So I googled the part number on them and they are 50 series. How do they sound? I have shorty headers and an o/r h-pipe. I currently have a bassani side exhaust and like the sound but have always loved the sound of flowmasters. I had 40 series on an 88 I had years ago and loved how it sounded. But am a little hesitant about putting the 50's on. I don't want it to be quieter than what it is now