Hi, I just want to circle back and post an update to this thread. I ended up trying 3 XLR cables: Kimber Carbon, Kimber Select KS-1116, and Cardas Clear Reflection. I didn't try the Zavfino Fusion because they were out of the XLR version at the time.
I ruled out Kimber Carbon after a few weeks. It's not a bad cable, it has a bigger soundstage than my Hero, but it is also a tad brighter in the high end, which is not what I want.
As with the Kimber Select, I find it sounds very close to the Hero on the Source to Preamp link. The Select is a little bit more forward, and a tad warmer. Soundstage is about the same. I can't say I hear a big improvement over the Hero. It confirmed for me that the Hero is a very good cable at its price. I then tried the Select between my Preamp and Power Amp. Wow, I was immediately impressed with the extra bass and warmth coming from the Select. That really sealed the deal for me.
As with the Cardas Clear Reflection, I like it quite a bit on the Source to Preamp link. It sounds very spacious and projects a bigger soundstage. Bass is not as deep and prominent as the Kimber Select. Nice details on the high end but with a tiny bit of brightness occasionally. Not as warm sounding as the Kimber Select, which I found it surprising because most comments I read about Cardas cables tend to state they are warm sounding. I then tried the CR between my Preamp and Power Amp, and I really did not like how it sounded. I sounded bright and thin.
At the end, I decided to buy another pair of Kimber Select and replaced both Source to Preamp, and Preamp to Power Amp links. I still have the Cardas CR, and still deciding if I should keep it. I really wanted to like the CR, it's not a bad cable at all, and I got it at a great price for an open box demo from Music Direct. Just that it my case, the Kimber Select satisfies the 2 goals that I set out to achieve: warmth and bass, although not much improvement on the soundstage. Another question that this exercise answers for me is that, the upgrade between the Preamp and Power Amp makes a bigger impact in my system.
Anyway, hope this helps and thanks to everyone's help on this thread.