Audio Research LS 25 MkII compared to actual AR production ?

Hi all and thanls for your forst suggestion.

Today I tried a Shunyata Black Mamba HC on the LS25. Difference between Furutech FP-3TS20 and Shunyata is great, but I'm puzzled about the bass that became maybe too dry (remember with spectral and wilson I *need* body ;-) ). Tomorrow I will continue my listening session.
Shunyata effort on sound is, generally speaking, invasive, and its contribution has to be evaluated carefully, IMHO (I love Shunyata but I'm conscious they are not cables for novices) .

Ref 5se. Good suggestion , thanks @lostbears
Ref3, thaks @mitch4t  and @adg101, my only concern it's -more or less- a preamp with the same age of L25, I'm not sure I want to buy an old equipment more.

Yes @audioconnection and @almarg , I'm aware of that.
DMA 200 S2 input impedance is 10.000 ohms and AR LS 25 MkII is 320 ohm in single-ended (now is connected in Single Ended, not the 600 ohm balanced).  The general thumb rule of 10x is respected and the most restricted Audio Research thumb rule of 30x is in the limits.
In the facts, i.e. listening, LS25mkII sounds great with no roll off or problems.
Of course, in balanced mode, the ss smp should be 20k minimum for the same rule.

I see Ref 6 (and Ref 5 se) has the same output impedance.

Thanks @almarg  for your contribution, I never stop learning !

I'm also considering the new GS Pre, phono input and headphone connector are a good plus. unfortunately there are not so much comparisons between ref 5e/6 and GS Pre on the net.
GS Pre's impedance output in SE is 250 ohm.