Product review (2 stars): I bought 8 new metric screws thinking it would be an easy fix, just bend the flange back to normal ...
Buyer beware. Some parts and manufacturing/assembly process are sub standard. My fan arrived fairly well packaged however the dual blower assembly had pulled loose from the main shell and there were some minor bent sheet metal issues. There are 8 small metric screws that attach the blower assembly to the shell. All but 1 were stripped. The blower assembly was more or less hanging by 1 screw. I bought 8 new metric screws thinking it would be an easy fix, just bend the flange back to normal and put in new screws. Nope of course this was not the case. 6 of the 8 holes in the flange of the blower assembly were stripped out too. I had to replace the screws with a slightly larger machine screw and tap the 8 holes in the blower assembly accordingly.
Also the blower assembly to shell mating surface does not have a gasket. This means some of the exhaust will escape back into the fan shell decreasing efficiency.
The next thing I noticed was the output adapter flange that mounts on top of the exhaust port and allows an eight inch diameter pipe to be connected is welded together but you can see light through all the joints. Again an exhaust leak issue except this would leak back into the house. I thought the idea was to get the exhaust out of the house?  After making the repairs I bench tested it and it seems to work ok. I will be applying silicone sealant to the joints of the output adapter flange when ever my kitchen renovation gets to that installation time frame .
Also the top of the unit was scratched up possibly from the loose screws? But it will be hidden up inside the cabinet hood and not visible.
To sum up my initial experience I would say the thin sheet metal is a low budget engineering design flaw. The blower assembly is somewhat heavy and the way it is attached leaves a lot to be desired. Hopefully Z-line will read this review and make the appropriate design changes. For $550 I expect a lot more for my money.