Dan... the PIVOTS are a MUST...
... the others fill a NEED.
Most likely when you pull your struts apart you will find the stock phenolic parts either broken or worn... like mine were.
The Pivots replace and re-center and make your steering easier. NOT ONE person has ever NOT raved about them.
As for the Strut Mounts and the Doublers, they fulfill a NEED that usually fixes (band-aids) "tweaked" towers and the resulting effect they had on the mounts because of excessive abuse!
A pothole could be to blame also!
The strut mounts can be banged back into shape but are a weak metal and the new Obert ones are supposed to be of higher quality. Plus, the rubber he uses is at least NEW and again supposed to be a better quality than stock.
The doubler's strengthen and reshape, or better, "hold" the shape of the tower.
I've only used the pivots but have NO DOUBT that if you NEED the mounts or doubler's, you can't do better than "Plaia-designed", Obert products!