Ok a local muffler shop has a dual exhaust special for $249.99 offering a magnaflow or flowmaster muffler. I have decided to go with the flowmaster 50 series but don't know what the difference is between the regular, Delta Flow, and SUV variant. I think the Delta Flows have less interior resonance?

http://www.youtube.com/watch?v=Q7zkm7w9QR0

http://www.youtube.com/watch?v=3TCT7sk5EsI

I know this isn't a F150 but....
http://www.youtube.com/watch?v=NA4L5ea84H8

So which one should I get?

 

The 50 series is designed to be fairly quiet but give you the increased performance that your looking for. The delta flow is going to be a little louder than the regular but fairly close. The SUV version is just made to quiet a bigger engine more efficiently. And the regular is obviously somewhere in between. Your going to get the same performance upgrades with all of them. The 50 series will give you the same sound as any flowmaster just a lot quieter. Honestly I never would understand putting anything less than a 40 series on because I like to be heard. But its your choice.

 

IMHO forget the flowmaster and get the magnaflow. I just went from a true dual flowmaster to a true dual magnaflow and I dont think I will ever buy a flowmaster again. For loud I would go flowmaster. For performance I would go magnaflow. My truck seemed very sluggish with 2 flowmaster mufflers.

What was your reason for picking flowmaster?

 

Both of the above replies are correct, Stinkbomb defined the muffler versions perfectly, and sgray is leading ya to the direction of the better sounding, lasting, and performing muffler.

 

I Swapped my dual flowmaster 40's for dual Borla and will never back.

 

I switched out my flowmasters and will never go back, go with the magnaflow