I haven't heard the Furutech GTX-D gold outlets. I do have a couple of the Maestro outlets though as well as the Porter Ports and the Oyaide R1. I had an Oyaide SWO GX but couldn't get rid of it quick enough as it was deficient on the top end, opaque and too full through the mids, and too full and loose on the bottom end.
How you'll react to the Meastro will depend on your priorities. For me, transparency and detail are tops as well as a focused soundstage and the Maestro outlets are the best I've heard in these regards. The Maestro is quite neutral as well and probably won't do much to tame the sibilance you're experiencing. I found the Oyaide R1 to tame some midrange brightness I was having issues with and it seems to have more control than any other outlet I've tried but it just isn't as transparent as either the Porter's or the Maestros so serves only to power up my powered subs through my PS Audio power plant.
I see that you're using the rhodium plated Oyaide SWO DX outets. I haven't heard these nor the matching 037 plugs but am very fond of rhodium as well. I have found that the IeGO 8095 plugs (rhodium over pure silver--not over copper or brass) are magical in taming midrange brightness (sibilance in some cases) while maintaining the highest degree of detail and top end air and extension. All of my power cords have at least one of these plugs on them. (I also use Oyaide 046 plugs). You can purchase the IeGO plugs from acousticfun(dot)com
How you'll react to the Meastro will depend on your priorities. For me, transparency and detail are tops as well as a focused soundstage and the Maestro outlets are the best I've heard in these regards. The Maestro is quite neutral as well and probably won't do much to tame the sibilance you're experiencing. I found the Oyaide R1 to tame some midrange brightness I was having issues with and it seems to have more control than any other outlet I've tried but it just isn't as transparent as either the Porter's or the Maestros so serves only to power up my powered subs through my PS Audio power plant.
I see that you're using the rhodium plated Oyaide SWO DX outets. I haven't heard these nor the matching 037 plugs but am very fond of rhodium as well. I have found that the IeGO 8095 plugs (rhodium over pure silver--not over copper or brass) are magical in taming midrange brightness (sibilance in some cases) while maintaining the highest degree of detail and top end air and extension. All of my power cords have at least one of these plugs on them. (I also use Oyaide 046 plugs). You can purchase the IeGO plugs from acousticfun(dot)com