Has anyone installed air bags or air "springs" to their vehicles rear suspension? I own a V70 and with the kids in the third row and the pop up camper or the cargo basket installed there is considerable drop in the rear suspension.

We are also looking to purchase a V40 and I thought I read that the rear springs fail alot. Would a rear air suspension be a economical option?

I am looking at the following product with particular interest:
Ridetech F7076 Ridetech Air Springs=

Any thoughts? Thanks!

Respectfully,
Tom