I have a number of vbulletin 3 forum licenses, I was going to make an upgrade. The upgrade prices are $175 for the forums and $250 for the suite. Why Does upgrade Cost So Much ?
You probably need to be asking this on their customer support forums. Either way, rather spend the extra $20 to get a new vB4 license and keep the current vB3 licenses untouched for now. I'm sure they will figure out some day that the asking price for upgrades is unjustified.