When I bought this GX 470 everything was great except for the suspension. Paint is excellent, motor runs like a top, interior is nearly perfect (except for some of the interior lights) and it even had some very decent All Terrain tires. Everything was rosy, except for that suspension.
The rear air bags leaked and I knew it, and the shocks were pretty much non existent. Going down the highway you could feel the tires just bouncing all over the place. I knew I wasn't going to keep this suspension anyway when I bought it, but it's going to be a little time before I swap it all out for an RST front and rear three link setup, so I needed something that I could put on it that wasn't expensive, that provided a decent ride and put the vehicle back to stock level if not just a very mild lift.
I looked at all the "kits" out there for swapping out the rear air bags for coil springs since I wasn't going to go through the expense of replacing those factory air bags and I even ordered a kit but later canceled the order.
Most of the kits out there for the rear are fairly simple. Some coil springs, an isolator for the top of the spring and in some case's a mount for the bottom of the spring. Throw in some shocks for the rear and a new set of coil overs for the front and your done.
Kits started at around $250 and went up from there to over $5,000 depending on the type of shocks you get and whether or not you even replace them. You can get just the rear coil spring setup and be done with it keeping your stock shocks if you'd like. Mine were so shot and had never been changed since they were new in 2004 that keeping them wasn't an option for me if I was going to live with this truck for a few months.
With all of that in mind, I decided to make my own kit. First I got rid of the factory air bags and stuff.
Next I headed to my 2004 4Runner sport with the 4.7 V8 and got under it for a good look at it's suspension. It has the Xreas suspension that is still running very well, but I was more interested in how the rear coil springs were mounted and what kind of mount they had. To my surprise, they have the very same mount that the Lexus has. So why are company's selling a kit that has another mount for the lower portion of the spring on top of the axle when the factory saw fit not to have one? Since my 4runner drove so nicely I decided to just follow their lead. I mean heck, Toyota has more money and engineers than I do so why argue with them over something like this. I found some 4Runner springs from my good friends at DeMello-Offroad and made my own 1" lift mount and isolater for the top of the coil springs perch and placed the spring in the same place the air bags were. They aren't going anywhere and there is no need for another mount on the top of the axle.
After I got the springs installed and drove around for a day like that I knew I needed shocks now. I did some research and found that for what I needed for a few months at most, was a good riding system that wouldn't brake the bank. I landed on the Bilstein 5100 setup that allows for a mild lift while providing an excellent ride and great suspension component quality for a relatively modest price. I got this entire setup for under $500. Well under!!!