Is it lifted? If so what method and how tall?
Have you ever had it aligned? Do you have those specs?
Ever replaced the shocks / Struts? If so what brand?
How many miles did you get out of your last set of tires?
Anything else you can tell us?
***Note*** - It is highly recommended that this system be installed by a professional technician with the appropriate tools and equipment to properly and safely perform the installation. If you feel that you do not have the tools, equipment, and knowledge to properly install these components...
Just remember that 4 Runners do not have a very steep rake like a pickup truck does. 2.5" lift in the front will probably have you around 1" nose high. But that is the style in SoCal!
If you go with rear springs, run the Bilstien's standard rate, they do actually ride better than stock!
Stick with the setup you are working with but do not run the ICON rear coils, they are progressive. Go with the Bilstein rear springs instead, they are linear. You are running a linear setup in the front and should do so in the rear for a balanced ride. If you want 2" rear lift, add a 10mm...
Bilstein Heavy Load (400lb) #36-281831 would work great on your type of setup, but they provide only 1.5" lift. You could run a small spacer with these to get to 2" if that is the height you really want to achieve.
OME Options:
889 - 2.5 - 3" lift - Medium Rear Coils
898 - 2.5 - 3" lift -...