Are you getting a lift kit from Downey?
If you aren't, I don't think I would go for a set of new springs. Chances are you will want a lift before you need new springs again and that would be wasted money. I need to fix my 1 gen rear end sag too, but I think I'm going to go with an add-a-leaf so I don't spend a lot twice. I know they say the add-a-leafs make it stiffer, but frankly, my whole set of leaves are perfectly flat, sitting on my over load bar.
In my case anything would be better. Don't know if yours are to that point.
Just my .02
Let us know what you decide.
Erich
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99' Black Highlander 4runner /
Garage Profile
Black powder coated 8x16 Wheeler Off-Road allow wheels / Husky floor liners / Thule MOAB rack / Custom Sub Enclosure /
Back-up lights
"I don't high-light my hair, I've still got a pair, yeah honey, I'm still a guy.
My eye brows aint plucked, there's a gun in my truck, Oh thank GOD, I'm still a guy!" Brad Paisley