Ordered the chopper and clamp (you need the clamp if you remove the chopper housing from the pump). Clamp is special because it's narrower than a standard worm clamp, but considering the cost, you might try to get it at the auto parts or hardware store. I didn't want to mess around with it so I just purchased it.
The chopper blade had broken off on an excess of junk my kids put into the dishwasher. Then the screen clogged with junk causing the weak spray pressure. Installing the replacement was no problem at all - no leaks, works great.