I just put the Tri-Ax handle on my Pro 5.0 yesterday...I resisted for as long as I could, but them I just had to do it - 5 min swap...too easy not to do it. And, ya know, I kinda like it. Up a little taller, over a little closer, and the handle, though it vibrates more than the steel 5.0 handle did, it seems to absorb more of the vibration so less is transferred into the fatknob handle I have. So in the end, it is actually quieter. Not that a little gear whine bothers me, but for some people, that's a concern.
I'd recommend just installing the Pro 5.0 right out of the box and see how you like it...then if you want, you can put the Tri-Ax handle on for a change.