I only went with the wide axles because I tried running traxxas geode rims, which I think are 1/2" offset, but I kept snapping the HPI 17mm wheel nut rim off. But, to go with standard offset wheels/tires, I had to widen it or the inside of the tire rubbed on the big bore shocks when turning, a lot. Granted, that was when I had the "hpi suspension conversion", which I think allowed for a tighter turning radius. I removed the kit in favor of stock suspension, but didn't try replacing the long shaft wheel axles with the short ones again.
Even with the wider axles on it with standard wheels, it doesn't feel all that wide and is relatively tippy when turning. The trenchers I run are the standard 3.8's, not the wider X type. I got them used to try them out, I was afraid they would be too much tire for me, but I liked them. I got the same ones for my brushless revo for Christmas from my wife.
I had the tires/wheels on the right on it before the trenchers:
The trenchers added a little bit more cushion, which has been working out really well and the grip really well on grass, dirt but seem to be holding up ok to concrete skate park bashing.
I also have 2.8" trenchers on my stampede 4x4. After getting those, I had to try a set on my savage!