There is no trial version of PlexTools. If you didn't get it with your drive you'll need to buy it. SpeedRead can be enabled manually via the drive's eject button (make sure the drive is empty and press and hold the button until the drive's LED blinks, the release the button so the tray opens and you can insert a disc). SpeedRead can also be controlled via PlexTools. When you enable it in PlexTools the setting will be stored in the drive so you can then, if you wish to do so, remove PlexTools. But why would you want to remove PlexTools anyway? It's really a must have for the PX-716A drive. Good luck and let us know how it goes.
Anyway: you were talking about "analysing stage" so I presume you are trying to copy a DVD using software like DVD Shrink? The analysing stage looks at the structure of the disc and this takes time and is not dependant on the read speed of your drive but rather your CPU speed and such. So, you will never see a high read performance in this stage. If you really and to test your drive it would be best to use a tool like Nero CD-DVD Speed and perform a Read Speed Test. Of course, PlexTools can also be used for that which even allows you to do a simulated Write Speed Test.