Title is kind of explanatory. If I have Qarl's installed would I be able to put CorePc's beautiful work on top of it?

Yes indeed. I do use both Qarl 3 redimized and some of the Vibrant omods. I use Qarls for all architecture, buildings, towns, sewers, etc. and I use the Vibrant textures for landscape, rocks, grass, etc. I think the vibrant landscape textures are better than Qarls. This combo works very well for me.

Thanks for the info.

Not to hijack this thread, but would Vibrant LOD and Vibrant LOD Normals be compatible with the UL-Complete LOD? Or would I lose the UL areas in the LOD?