Great review. I agree with pretty much the whole thing! I'll let others speak about the sway bar as I'm obviously biased.
The next thing I'd love to do would be work on the over-assisted power steering. It's just way too much at lower speeds. I haven't had much luck hacking the system yet though. It seems pretty smart.
View my fuel log 2015 Mirage DE 1.2 manual: 47.2 mpg (US) ... 20.1 km/L ... 5.0 L/100 km ... 56.7 mpg (Imp)
But, in reality, almost all shocks start losing their edge before they hit 30k miles. More so if they live a hard life... lots of speed bumps and that sort of thing. Do they still work? Sure. Do they feel like they did when the car was new? Nope.
The first thing to go is "low speed damping". That has nothing to do with the speed of the car, it refers to shock shaft piston speed. Low speed is things like smooth bumps, steering inputs, that sort of thing. You lose the crispness of the steering. If you're losing that in the rear, it makes the whole car feel a little wallowy.
You can sort of address the issue with a rear swaybar, but if you HAVE bad rear shocks, that's just a band-aid.
If you want to wrap your head around what I'm saying... drive your Mirage to a new Mitsubishi dealer. Pay particular attention to how it responds to your steering inputs and how it handles bumps. What's the front of the car doing? What's the rear of the car doing? How responsive does it feel? Now, go drive a brand new, unmodified Mirage. The only real difference is the age of the shocks. The cars aren't old enough for bushings to be an issue. Tires should be the same. The difference between a 30k mile car and a brand new car = shocks.
Simplify and add lightness.
View my fuel log 214 Mirage ES 1.2 manual: 41.8 mpg (US) ... 17.8 km/L ... 5.6 L/100 km ... 50.2 mpg (Imp)
My Mirage got modded for autocross shortly after I bought it. Adjustable coilover shocks all around.
But, I've had my wife's 2007 Miata that needed shocks by 25k miles. And more recently, my Kia Rio driver's ed car was feeling mushy by just over 30k miles and by the time it got to 40k, it was making me absolutely crazy (plus feeling borderline scary at speed with a cross-wind) and we replaced them.
Most of my personal cars get upgraded shocks. Something like Koni if I can get them. Stock shocks or stock equivalent shocks will lose their edge by 30k, and be downright dead by 60k. A lot of people drive on them, anyway, and it's personal preference as to how bad you want to let them get before replacing them. A good performance shock like a Koni or Bilstein will last a lot longer.
The Rio got a replacement set of standard KYB shocks. They started out notably stiffer than stock, so I expect they'll take a year just to get to the level of typical stock shocks... and maybe last a bit longer than the stock shocks did.
My last DE car when I was working for another company (vs working for my own company) was a Versa that had 50k on it when I got it, and the shocks were already pretty soft. By the time I was done with it, it had over 80k on it and I hated every minute behind the wheel. Driving over 60 mph on a highway that was less than glass smooth was disconcerting. But, the car was under warranty... and a dealer won't replace a shock under warranty unless it's "failed" (obviously broken or leaking) no matter what it feels like. And, of course, the boss wasn't going to pay dealer rates to have them replaced.
On our Rio, we bought a set of shocks that cost us maybe $250 for all of them, and replaced them on a Saturday afternoon. Worth every penny!
Back to the point: If you're driving a car that has 30k+ miles on it, and you feel like the body roll isn't controlled enough... it's probably partly due to the shocks. Body roll in itself isn't a bad thing. It's the lack of control that's bad, and that's the function of the shocks.
Simplify and add lightness.
I guess shocks will be added to my maintenance list for my '14 and since my '17 is pushing 30k miles it should have a new set as well.
Zero, 2014 ES Plus 5MT, written off but not forgotten.
Zero II, 2014 SE, 5MT, climate She's HOME now!
Shelby AKA "Cute", 2017 ES 5MT, A/C.
Mirage owners look at the world differently than everyone else, but in a better way
We're driving the Beetle of the 21st century, the greatest small car now available!
View my fuel log 2017 Mirage ES PLus 1.2 manual: 39.0 mpg (US) ... 16.6 km/L ... 6.0 L/100 km ... 46.8 mpg (Imp)
Shocks wear gradually over time. So even though you drive your car every day, you don't realize how the ride quality has degraded because it happens slowly. Then one day when you finally replace your shocks and suddenly you notice a huge difference...like Loren is saying.
Here's a quote from KYB's website...
Also remember that worn out shocks/struts can cause serious tire wear issues.Even on well paved roads the shocks can move up or down 1,500 to 1,900 times every mile: In 50,000 miles that can exceed 75 million cycles. Over time, performance tends to decrease gradually and the motorist usually doesn’t realize how much handling and control is lost. Replacing shocks and struts after 50,000 miles can keep the vehicle performing as well as it was designed and extend its life expectancy.
Here's a good video series about shock absorbers...
Why Replace Shocks Part 1: How to Tell When They Are Bad
View my fuel log 2015 Mirage ES 1.2 manual: 51.9 mpg (US) ... 22.1 km/L ... 4.5 L/100 km ... 62.3 mpg (Imp)