I'm running the 50 series and use to have the 40.... the 50 is nice rumble outside and quiet in the cab... you'll be happy with it

 

I've also had both, I like the 50 a lot better.

 

Sounds like a toss up between the 50 delta flow and a magnaflow. I love the rumble of the flowmaster, never really heard a magnaflow with headers on a dodge. I am also considering putting on a high flow cat, but it seems pointless with headers. I have an o2 sim for the post sensor, but maybe the cat might be the ticket. Do you think i'll see an improvement towing and wheelin with a high flow cat on? My mods are geared to mid range powerband. Little more backpressure might help the low end?