vandersteen quattro ct owners what speaker cables do you use? bi-wire?

I own the Quatros and use MIT Shotgun S1 biwire with outstanding results. Used AQ Volcano biwire for awhile but the MIT bring a more pronounced 3D soundstage especially in the bass region and more meat on the bones. Either one are extremely good and I’m sure the Galileo would be outstanding as well with the proper terminations. 
The IC’s one uses will also have to be considered as the Quatros use the inline passive crossovers and for this application I use AQ with DBS stepped up to 120vdc. One will need to choose RCA or balanced on the crossovers at time of purchase. I’m sure your SR IC’s will be an excellent choice as well. 

After listening to what the AQ William Tell's did to a pair of Vandy VLR's, I bought a set for my VLR's and Treo's.
As your Quatro's have built in subs, you might want to think about the new AQ power cords.
I auditioned at Audioconnection (PM him- he is here on Audiogon, same name) with Pete Swartz (ctsooner- PM him,too). Both he and I were blown away.
I have no experience with Synergistic Research.
But, I have to say the new cables Garth Powell is making for AQ is something you should try.
Lastly, you should sign up at the Vandy Forum on the Vandersteen website. You might find other SR users there.
Bob