I can also confirm that it fits and I have not experienced any turbulence. I've only noticed what I would call normal fan noise, no vibrating or whistling.
Something to note though for other people considering the MSI GTX 1660 ti Gaming X and a Dan Case A4, is that it just BARELY fits. I had to zip tie the card to the case spine and put little spacers (felt pads with a sticky side) between the shroud and the side panel. Without the spacers the side panel would touch the fan and prevent it from spinning. That being said, the panel is closed on the case, the fan spins, and temps and noise levels are great. If you are willing to do some super low level mods, the card works great with the Dan Case A4. Hopefully other people find this useful.
@dondan happen to know if an EVGA FTW3 1080ti will fit with the Asetek 645LT in the v3? Have gotten a ton of conflicting answers when asking people, most people aren't sure about the radiator pipes hitting the pcb.