You'll be better off with the C59-329 based on what you posted. I will be running them soon when I install my rear bumper. I have dobinsons now that will sag for sure if I put the bumper on without the new springs.
I don't know why this keeps getting repeated. KDSS is proven across multiple vehicles and rarely has issues.
My 2015 has 75k miles and I have had zero issues with the KDSS system despite multiple suspension modifications and moderate off-road use.
This forum likes to parrot that KDSS is...
Mule Expedition Outfitters (Issaquah)
Auburn Car Repair & OffRoad
Truline Bellevue
Torfab (Everett, Landcruiser only for the most part)
Michael's Toyota of Bellevue also will do a lot of suspension work on 5th gen 4runners.
Les Schwab's Manager in Bellevue (Bel-Red Road) says they can also do...
There's no difference between the two models and they both have such low miles I would go with the cheaper one. That being said, you may get better financing rates on a newer model.
This thread (especially the first 15-16 pages) was painful to read through. You can see some commenters eventually come to their senses over time. It played out almost exactly like it did where I work. I live in Kirkland, WA where this all started and I was getting made fun of in early March for...
If I had to do it all over again, I would avoid KDSS. I've never been happy with my suspension setup.
EDIT: I say this only because I like to go off-road at higher speeds and it feels too stiff. I am super happy with the on-road performance.
Really glad that I'm not the only one experiencing this issue, but I cannot get my local dealership to take it seriously at all. They blame my tires, my lift, etc. I show them the service bulletin and they say they can't replicate it so I just deal with it.
What are the long term negative...