There's a $50 difference between "I own another version of Sonar Producer" and "I own X3 producer." but only during the discount offer period. Then all Sonar Producer owners will pay the same.
So your out of pocket what ever you payed to upgrade from 8.5 minus the $50 for now.
Not to sound like a jerk, but I think it was pretty clear that there was a new version coming out and that it's always been this way. It is wise to upgrade at the beginning of a new release, not at the end of it's cycle. Most users have gotten their value out of X3 over more than a years use.
Such it is with all software. But look on the bright side, you can use Sonar x3 for ever and ever. It's a good version to own, just like 8.5 which I still have installed.
I'm not sure what your problems are but as Bob and the gang are saying , keep posting your issues and it can be solved, we never give up without a fight!