I certainly take your word given your wealth of knowledge on a lot of these things, but having just replaced all my struts and associated bushing components on my SV6, I cannot for the life of me tell any difference between stock FE2 struts and the OESpectrums. I noticed that Monroe doesn't list any struts for Calais FE1.5 in the front, and the only rears they offer are a different part number to the FE2 OESpectrums so there is different valving it seems.
On the same road loop I do from the city through the hills to the Barossa, the OESpectrums feel excellent with stock springs + all new OEM bushes and I was trying my level headed best to feel any changes or differences. Only difference was SuperPro Polyelast strut tops, which again I can't tell any additional harshness.
Not saying GT Sports aren't "better" for spirited driving, but im very happy with the OESprectrums for a daily. The front struts are identical in everyday to the OEM's, the rears are a significantly bigger in diameter to the OEM's, presumably for more oil volume. If I had an SSV with FE3, id have certainly gone GT Sports