Question for Levinson owners

At the present time my interconnection are CZ Gel by Madrigal and there clam is that this cable has no coloration and is transparent they also clam there is no filtering of the signal for "euphonic" effect.

Now on the other side of the coin Nordost clams there interconnection the Valhalla is the most neutral cable interconnection ever developed.

I just want to know if anyone out there ever compare these two cables, and if so is it worth it to me to upgrade. In other words, I already have the Nordost speaker cable would adding the interconnects make that much of a difference.

My system
Mark Levinson 390s, 380s and 23.5

Interconnects: CZ Gel

Speaker cable: Nordost Valhalla