I actually already submitted a support ticket for ReBAR support and mentioned it HERE, Changes are slim at best 
Basically, Arc on Framework 11th Gen is unusable, without ReBAR support the performance is about 50% of what it should be (when stuff actually loads) and I get random crashes daily (when docked with Arc) even if I am not using my laptop for anything (I even swapped the Arc with another one just in case the crashing was a hardware issue).
I am forced to put my old GPU back in and very disappointed / frustrated… then again this is exactly what I was willing (worst case) to do for being a “Guinea Pig”