I added 2 leafs from korean 1.5 tn truck under main leaf. Yes, they gave me lift. But there is almost no flex.
When one of rear wheels drive over something bigger 3", rear of vehicle rolling and some strange sound heard from there. Also I noticed deformation, front top corner of driver side rear window is loosened, almost 1cm of gap between seal and body. Now I'm finding donor leafs for more comfortable ride.