All my opinion..... which is what a muffler choice comes down to every time anyway!!
In WI, it is humid. Non-stainless flowmaster of any type, if you drive the vehicle quite a lot(like a daily to work) will last maybe 5 years. Not counting winters here, just normal driving during the summer. The humidity in the air plus heat cycles a couple times a day = rot out.
Magnaflows of same non stainless type make it an extra year.
Anything by Walker of non stainless is 4.
I mean they won;t blow out, but when you look they will be rotted and you will be worried the tail pipe is going to let go.
Now, for limited runs, stailess longevity might not be a worry. If you get ten years out of a regular one because of intermittent use, who cares then! Is getting 15 out of a muffler that costs 4x as much worth it?
Now for sound, totally my opinion......
Flowmasters sound good in smaller diameter, but 3" and up NEEDS a big block or they will drone bad. Or tall gears to push RPM up. Buddy had dual 2" on a chevy 305 car and it sounded mean. Different buddy put a 3" dual set on his 5.0 and you had to roll the windows down in the car or go deaf.
Magnaflow have a more "pulse-y" sound, still smooth but not as echo/roar blended as a flowmaster. I like stainless magnaflow. Quality is not as high as it should be for price but they don't give up classic sound IMO for the stainless.
Gibson makes a top quality product and you buy what you want for volume. Very simple explaination they have for it: you want less noise, they increase offset of pipes in the chamber to force the gas to change direction more. More noise? straight through. Quality products.
Dynomax is a budget brand. Proper size for application and it will sound pretty good, but not as good as it could.
Modern Borla has gone full blat pipe, and sells to new corvette guys and obnoxious mustang guys. Yuck. Not only does it blat and pop under throttle, it pops like a handgun on decel and there is no classic V8 rumble, just a raspy howl. Combine with X pipe for maximum millenial obnoxious mustang sound.
NOS 1990's Borla? Best sounding muffler ever. A full system? Best scavenging/performance/sounding systems. No drone, loud when you want it, not so loud for in town at 25mph. Good luck finding that stuff anymore.
Bassani stainless.... hard to find. Super high quality. Like, could hang it on a wall and admire it good. They made bike stuff, so they know how to make things sound how they want.
Glass packs. I think people know what they sound like. Younger folks will grin ear to ear if they haven't heard one before. I stuck a stainless built, straight through 18"-er on my dakota when I took the cat out(totally plugged) to act as resonator because I haven't done factory muffler yet. Made the truck instantly sound like a 70's beater hot rod. Makes the boy laugh when I rev it in the driveway or do righteous burnouts.
my personal preference for Mopars for sound ONLY(performance is different)
Manifolds, not headers.
A custom Y pipe, usually 2" into a 2.5 or 3 single(small block)
Glass pack, but a LONG glass pack. Not some silly 12" firecracker inducing pop maker. Last one I used was 24" on a 2.5" for a spruced up 318 that liked to spin.
Tail out behind rear wheel if possible to help keep sound out of cabin. Less important on a truck.
Big blocks need a dual set up. I prefer dual 2.5's, but it needs to be mandrel bent. My favorite so far was some not quite straight through Gibsons. Enough to take the rasp out. H pipe is better then X on a big block.
I had a full stainless Magnaflow on my 2001 ram 360 magnum. Sounded really mean, but maybe a bit loud at low rpm for daily driving in town.
The 94 Mustang I built got an "offroad" bassani stainless X, into a NOS 90's era Borla cat back system. Sounds absolutely like a dream. (boy owns this now) Modern Borla can go die somewhere. Old Borla they knew what was up.
Again, opinions, every one has them.
