Looks like your getting as much flex as you can with an IFS truck. But do like was recommended and remove the shocks, so you can measure how much flex you have the capability of. Make sure you have a buddy watching your brake line while doing so. As long as you're running IFS, your limiting your ability to flex anyway, but getting a little more in the rear might be nice.
Also, before you remove your shocks, measure them at "Full Extension" then measure them again at full extension after they have been removed. This will help to confirm that the shocks ARE the limiting factor.
If you do decide to reposition the top mount onto the crossmember, keep in mind that the farther they are from perpendicular to the axle, the less they will help.
