I wouldn't necessarily consider the Speltz anti-ics warm or warmer. Although they are perhaps slightly more full-bodied than other similar performaning ics.
I've compared the Speltz'ics to other cables that were performance competitive to the Nordost Valhallas (but not the QuatroFil) and the Speltz were easily superior.
In fact, thus far, there is only one ic that I've heard that is better performaning than the Speltz anti-ics and that's the Audio Teknes, which is what I currently use.
Funny thing about this hobby, the SignalCables Silver Resolution Plato mentions weren't even in the same performance league as the Speltz ics in my system. And I highly regard Plato's opinions. Especially when it comes to amplifiers.
-IMO