1996 5.9 liter
So I have wanted to put on a flow master super 44.
1. Will it increase performance and mpg? I don't really want to mess with my manifold and cat convt. So If I just do flow master and new pipes after the cat will it still affect performance?
2. Will the flow master and new pipes after with a resonator be louder and deeper? Thanks

 

Most people don't notice any change in mpg simply because the truck is going to sound a lot nicer and it's going to be hard to keep your foot out of it. There will be a slight performance increase due to the less restrictive flow of the muffler but you may not really notice it. The super 44 is a nice sounding muffler as it is, im planning on just getting a single in, dual out setup and dumping both pipes in front of the rear passenger tire.

 

Ok so I'm gonna do the same thing except have them come out behind both rear tires then put resonators on both. Also I'm adding a spectre cold air intake because I heard good reviews and it's cheaper than k&n. So will this combo them give me a performance and mpg boost?

 

Just changing the muffler won't give you any performance increase at all. Nor will it improve fuel economy. (initially, it will be worse for the reasons already stated.) If you want better performance by doing an exhaust mod, headers, and y-pipe are a requirement. If you don't change those, nothing else is going to matter.

 

Ok that's alright I'm really dong it for sound s I will just do the muffler then. Will the intake still do anything?

 

It will flow a bit better than stock, simply because it doesn't have the 'fan folds' in the air tube. Will it be a noticeable improvement? Nope. You would get just as much from simply changing to a better flowing air filter.