Only if your pump is a 12WJ will you be able to use a place diverter, or any diverter like it. Also, if it is a WJ and you are going to install a place, you need to have the nozzle bored out of your bowl. In a place div, the nozzle of part of the diverter because that's how all the other mixed flow makes are setup. Therefore, you would have 2 nozzles in line if you have a Jacuzzi. If you have access to a descent sized lathe you can do this yourself. I chucked mine up and opend it to the vanes. I left about a 1/2" lip so I could still use the stock O ring seal. According to MPD, this is all that needed. I however didn't like the uneven transition from the bowl to the palce div adapter. I made a stuffer from billet that filled this void. Here are some pics.
http://www.beached1.homestead.com/files/Pump2.jpg
Oops. Sorry, I thought I had a url for my billet stuffer. If I get some time later I'll post it.
Hope this helps.