LONDON Decca, Tzar DST and similar cartridges

I’ve ordered the DB Systems DBP-6 MC Phono Resistor Loading Kit to run the Decca Reference at 15k ohms. And by adding a 130pF cap I can bring the capacitance up to 220pF.
I’m curious:
What sonic differences have others experience when running it at 47k and then at 15k?

The 15k impedance in combination with the added capacitance creates a damped electronic circuit. The Decca/London design suffers from an inherent high-frequency resonant peak, plus ringing in the time domain, which the damped circuit addresses. I was tutored in all things Decca by the Master, Harvey Rosenberg. 

"ringing in the time domain"

I'm not sure what this means.  Can you say more?

Never mind; just Googled it.

I've been looking into this cartridge and have been fascinated by its uniqueness and the myriad  necessary set up parameters to dial it in. I've spoken to Warren who gave me the thumbs up after a little light grilling to try a super gold. I've not pulled the trigger as loading is not something I can change with my phono set at 47k and I'm hesitant to jump until my pre allows for this. Curiously, The issue of resistance loading of my preamp did not come up with Warren only arm and set up experience. It was not something I was aware of on my part and thought to ask about at that time. 

One other question/concern I have after reading this great thread is does the lack of soundstage width that Halcro mentions twice above consistent with other users experience?