I am considering replacing the stock exhaust with a Gibson, which is basically a catback system. Does anyone recommend replacing the catalytic converter as well? My 07 Eddie Bauer has 65,945 miles. I'm simply trying to gain a little extra horsepower.

 

I replaced stock muffler with magnaflow. Was going to do a cat back custom system, but shop said stock pipes were already 2 3/4" diameter so didn't really need to upgrade. Gained sound, slightly more power, and 1-2 mpg increase when my foot's not in it.

 

How does that magna flow sound/cost compared to Flowmasters?

 

Typically Magnaflow's sound is more consistent and more mellow than the Flowmasters. With the interior volume being so large on the Expy's there is more room for exhaust drone to be very noticeable. The Flowmasters are notorious for drone, but they sound great if you can deal with the interior noise.
The Magnaflows are generally made from stainless steel, whereas the Flowmasters are aluminized steel. The Magna's will be more expensive, and typically outlast, the Flowmasters.

Just depends on what your ears, and your budget, can handle.

 

So if I wanted to do an exhaust with NO interior drone, what would be the best bet?

 

Stock

Honestly...exhaust drone is a funny thing. Can vary between two identical vehicles with same setups. Every engine has a harmonic sweet spot.

 

I got Flowmaster and got NO drone. Cant even hear it on the intersate. Just in town.

 

You also don't have 40-50% of your passenger compartment over the tailpipe section.

To the OP, you should check out Magnaflow and two more expensive options: Gibson and Borla.
Between those three you should get a nice low mellow tone without the scream of the Flowmasters...unless of course that's what you're after, pure noise.

I had Flowmaster on a 5.0 V8 Explorer and it was pretty obnoxious. I won't go back to them again.
Just my $.02

 

True about not having passengers over the tailpipe. But I would never describe flowmaster as "screaming". that's a joke! It's really not very loud at all. I don't know what series flowmaster you had, but mine is mellow and low. It sounds good. OP can go with whatever he wants, and I've heard magnaflow is very good, but it is twice the price also.

 

An important thing to remember, there are many, many different Flowmaster mufflers, some with much more drone than others. And the large interior volumn of these vehicles really amplifies the drone.

To the OP, try Stainless Works. They have a bolt on 3" cat-back system.

Stainless Works - Performance Exhausts and Headers

I had a Magnaflow 3" system on my 05 Expedition, and cut that POS muffler out in 2 weeks (terrible drone) and replaced with a Stainless Works muffler, problem solved. I also use their complete system on one of my BOSS 302 cars. Good luck....

 

I ended up cutting my muffler out and putting in a powerpack muffler. It is quite at idle and gets throaty when it needs to. You can hear it at highway speeds, but there is no drone.

 

I will do, and have done since the expy, Magnaflow exclusively. Many of my friends have done FM and enjoyed them, but end up replacing them in a lot less time than they thought. I'm all about Stainless Steel! Another factor to consider is location. Where you live and the conditions you deal with will have an affect on aftermarket parts as well. Sound is slightly less loud than FM, but still worth the upgrade. Some Magnaflows are smaller diameter too.