here is what 6" lift and 35's look like, imo i think the 35's are too small now
wanting to go 40's and chopped fenders...still need rear control arms and a few other things first

 

4in superlift and 1in body lift on 35's

 

The less caster you have in place the more minute the positive feedback mechanism needs to introduce death wobble. Same goes for toe and dampening. Caster, toe and dampening don't directly effect the positive feedback mechanism, they mask it.

A bigger lift without suspension geometry adjustments can bring to a head components that are the positive feedback mechanism that promote death wobble. That doesn't say that it's for sure going to happen, but the margin for error in the other components becomes slimmer.