Well, an IFS will handle much much better. When one wheel hits a bump on a straight axle it affects the whole thing, but on IFS, only that wheel is affected.
Straight axles can handle the biggest loads, which is why I decided to stay with mine instead of going forward, which would have changed my 1 ton rating. This is why the big trucks still have straight axles and king pins.
All the mods you suggest will help, but its a pretty big leap forward to get to IFS.
