Glue sidewalls on front tire. Other things I tried...more caster, more camber, softer front spring, softer side spring. Less sauce on front tire. Move motor farther back with smaller spur (keep same ratio). Aluminum chassis helps tremendously too.
I went from 1.5 to 1 on camber this weekend at the Hudy and mellowed out the rolling on my X1 18. Also, i seem to roll more if i add caster. The rest is spot on, in my opinion.