Hi onokai
I've had both the older Nikkor 105mm and the new VR one - and have used both in Subal housings, Type 3 and Type 4. My Type 3 housing was for a D300.
As you have the Type 4 housing, you'd have no problem with the wider barrel of the new VR 105. I was able to get it into the Type 3 housing but had to be careful the AF/M switch wasn't pushed when putting it into the port. The VR is a chunky beast.
I do find the new VR 105 better than the old in terms of focussing. It's just quicker and quieter. The older 105 chugged along and got there eventually. The VR is speedy. I think it perhaps "hunts" less than the older 105 - but that is a bit of a subjective view. As far as sharpness is concerned, I'm not sure I can see a difference. The new one is certainly very sharp! I think I read comparisons on Wetpixel some years back; and I'm sure if you google around you'll find comparisons on the web.
Is it worth paying for the VR if you already have the older 105? I was able to sell my old one for a fair price so the cost of the upgrade wasn't huge. And so, for me, it was worthwhile.