Oh, I think we can all relate to the nightmare of replacing a $30 vent fan!

Here are a few things I have found that make the job easier:

-Sometimes I an able to move the fan/motor assembly from the new unit to the old mounting plate;
- I can usually reach the mounting nails from below, with a long saws-it-all blade;
- From "Paws Off" tools, I was able to get ($30) a carbide grit rasp that fit in my saws-it-all. This rasp is a dream for making minor adjustments to poorly supported or water damaged drywall.