I have been testing this plugin for weeks now. When you install it, you will have a choice between the legacy driver and the "new" driver. I have had so many issues with the "new" driver, that I had to toss it aside. The new driver supports MSP 2013 SP1, whereas the legacy does not.
CA support wrote up one of my defects : that we have Fixed Work as our default for project. the New driver always changes all the tasks to Fixed units, thus messing up the entire forecast (we do forecasts in MSP which then lead to populating the cost plan in clarity ). There is also an odd message that pops up with the new driver about the task end dates and actual through dates and no matter what option you choose, the system wipes out of overwrites your task dates and forecast.. there is a long list I have open with CA support,, so be on alert, depending on how you use MSP. The save message is a tiny little message in the lower right of your system tray. When it is done,then a message will display. But, if you click on the project while it is saving it can lock up-- so to me, that is a poor usability change to not be able to clearly see the progress of the save.
Anyway, for me, I was able to install it on top of the 13.3, but then I also tested with a full uninstall (as mentioned above). Either way, the plug in installed, but again, depending on which driver you choose and how you use MSP, you may or may not experience issues. The legacy driver still has some of the same critical defects that exist with today's interface. I have an ongoing case... Good luck!