Tried both the SL & the SX. Two different worlds. I think the SL are made for those rigs that aren't terribly afixed to the idea of great sound. They can take off the edges and ease up the too bright highs... like #80 sandpaper. you'll definitely wind up with a smooth sounding reproduction. they were too smooooth for me. The SX are another story entirely!
I think the key in spkr wires is finding some which add or subtract nothing or very, very little. I also like the idea of keeping with the same brand along the path as is poosible. Power cables too. For a long while I had Voodoo and then Shunyata... now it's more Shuyata & Elrod. Another one of each is perhaps on my horizon. So depending on which ic I use to upgrade the Magic IIs, may indicate which brands of spkr wires I'll go with, as they'll be of the same brand as either IC.
'course... this is highly speculative, and who knows what will be 'to me' next. I'm leaning towards the Oppo BDP... then wires.
Currently I'm getting up the gumption to attack some fiberglass & mineral wool to DIY some traps. yeech.