I dont suppose you tried taking the roll bar off and running the VLA as short did you si? Why did you add the roll bar in the first place? i know you said it stopped the front diving in, but was that just the front end folding over? If so, when that happens i shortern the vla, seems to work for me.
Just a thought.
Cheers for sticking that up though, it'll certainly be one to try out.
Also were you running lipos? have you tried putting more weight on the front of the battery strap to move the weight forwards a bit. That really helped at worksop last time i was there.