Hi Dougie,
I think what Alan is referring to is the frame mounts for the shocks. Uprated shocks (read firmer) would add to the wider tire's affect on the shock mounts that were designed for skinny tires that gripped less than the more modern tires, like what I have on. In addition the lower control arm mounts might not be up to the task of these higher cornering forces. There are plans somewhere on the internet to beef the control arm mounts up by welding gussets on. I can't find it right now, thought it was the Nasty Boy site, but didn't see it there in the tech articles.