Unless you are going to add heads, new cams and an intake manifold
do not waste your money on exhaust systems.
Want a louder exhaust, use turbo mufflers.
The stock engines on these heaps are so limp, a Honda with a fart can gives MN12's a run for their money.
If you want 1/4 mile times to drop like a rock, 3500+ stall and 3.73 gears.
Of course this is all N/A.
Forced induction is not my style.
Also my junk has long tubes, by Sean Highland Motorsports.
They still have a pair, brand new.
While I agree with the accuracy of your statement, I disagree with the idea that it's worthless.
My car is a toy, a hobby, and is the lowest priority on spending money behind my home/groceries/wife/daughter/pets/entertainment. That said, I tend to start small and build up as money permits. So, a dual exhaust would be one of the first things I buy if I were starting with a car without, as it is relatively inexpensive, easy enough to do in the garage, and is a good "supporting mod" to everything else that comes later.
I am of the opinion that building a good supporting platform first is more important than starting with the big stuff like engine/transmission. So, Exhaust, suspension, wheels/tires/brakes, rear end, driveshaft, transmission/torque converter, then engine is the order I go in. I want to do jobs once, and do the entire job if I can, before moving onto the next thing. So, if I'm going to do an engine (which I'm doing now), I'm going to go as far with it as I can afford, in as short a time as possible so that I don't get tired of not driving my car.
Everyone has different priorities, but putting a free-flowing exhaust on the car can do nothing but help, and helps build a better baseline for when you do more stuff in the future in my opinion.