Panasonic "Whisper Thin" -- Bathroom fan replacement

This was kind of a nightmare. My old builder grade Nu Tone bathroom fan&motor stopped working. I found an exact replacement for the motor and blower cage. It was a five minute replacement and worked great, but it was VERY LOUD. 5 Sones. Didn&say that anywhere when I ordered. So I decided to buy a Panasonic bathroom fan, because they use a DC motor and are very quiet. I got the FV-0810RSL1. Big mistake- most likely my fault. Do your research before purchasing. This fan was made to be installed where access to the attic was not possible- it was meant to be installed into the joist from the bathroom. Large hole, and it attaches to the underside (room side) of the joist. I had a ton of attic access. Because of the way it mounted, I had to cut more sheetrock than necessary, and patch it and paint. Also be aware that when replacing a large round fan (me) with a small square fan (also me), sheetrock, joint compound, sanding, priming and painting will be needed in addition to installing the fan. Just think it all through. If you have attic access and are installing a Panasonic fan, get one that includes a "Flex Z fast" bracket