I had jfusion 1.7.8 with vbulletin 3.8.x. which i purposely selected since it's frameless. VB as MAster and Joomla as slave (best pair, since i'd been trying to get the best result). at first it worked good and i added some vb's mods. The problem started when one registered. and tried to get in the forum. Some embarrassing error messages kept popping up on screen. It took me 1 months to fix by asking lotsa sources mainly jfusion, but had no happy ending. (I liked discussion bot and user activity though). I think The support team on forum didnt really understand the topic errors given (It's free and no pay, that's why) I got rid of it with 1 simple conclusion that JFusion IS NOT ready yet to bridge Joomla with other softwares running on 1 server. The good thing is that it's FREE. Thank you
Since you have having problems with mods, we can only assume that you are using frame less integration. A mod can in may case be seen like a car part for car x you try to fit in car y.
As you can image parts will not always fit. You Will require to modify jfusion to apply the changes properly a global variable.
The support forum as you call it is not for support anymore have been so for a year or so. go to the support section.
If you conclusion is that jfusion do not work, that is your choice.