It's not as simple as that. Any inverted style coilover on the rear of a Subaru will not go up and down as it should because the strut does not point anywhere near the contact patch of the tyre. Conventional (small diameter) coilovers don't suffer as badly because the shaft is constantly being oiled and the friction is much less than the surface of a 40,50 or 60mm inverted like a DMS. That's why Subaru (and Prodrive etc) use large diameter coils that are offset toward the contact patch of the tyre. WRC Subaru's (in the rear strut era) used different rear hubs that had the strut directly over the hub centre. It's not a myth, it's a problem that suspension tuners have been battling for years.