I am interested in beefing up the rear springs on my 2013 Fit Base.
I found Firestone air bags, for $99. Has anyone used them? Opinions?
Any other options? I want to be able to have a softer ride, when not a lot of weight in the back.

 

Firestone air bags won't replace your rear springs. They mount inside the springs and are used to combat overload conditions that cause the rear of the car to sag. My suggestion is to look up the large DIY threads concerning Monroe Air Shocks. Very inexpensive, very good ride quality, and excellent overload protection. I carried two people and 960 pounds of cinder blocks on the back floor of my '09 Sport with no handling problems and no bottoming out going over dips and RR tracks.