I´ve only used parts of the mod to in order to make Red Bull stronger, slow down Racing Point and give Williams a boost.
Red Bull seems to be stronger but still a little bit to slow to constantly challange Mercedes. Racing Point definitely is slower and the midfield is much more mixed up now.
Williams is stronger too and both drivers are much more competetive than before.
However in my second race (first race where Williams brought upgrades) they finished P14 and P15 but the game moved them down to P20 and P21. Remains to be seen if this will happen more commonly now and the game changes their result by simulating the rest of the race with their normal perfomance "in mind" or if it´s just a rare bug from the base game itself. If that bug is not connected to the mod I can really recommend using it.