speakers cables for Lavardin and Harbeth?

They're very different wire configurations, so it might be worth some cost and effort. What type improvement are you hoping for?

BTW, the Monoprice 4-conductor 12 awg OFC wire is very reasonable, and very good if you can DIY the connections.  Right up their with a lot of the common "better wire" names.

I have the HARBETH 30.2XD’s driven by a REGA OSIRIS integrated amp, with a REGA ISUS VALVE cdp/DAC and MOON 280D MIND2 streamer/ server/ DAC source .

MY EXPERIENCES

I. don’t drink Amy of Alan Shaw’s pontifications and force-fed KoolAid that speaker cables don’t matter with his HARBETH speakers. After much personal and hands-on experimentation with many options including, inter Alia, BELDEN, ATLAS, CHORD, NORDOST FREY, VAN DEN HUL  and a myriad of other “budget” vablesc I thankfully landed on premium build CARDAS CLEAR REFLECTION speaker cables as best of breed in my system .

I run a full CARDAS CLEAR model cables array in my system, but but I specifically experimented and chose the REFLECTION model specifically for the speaker cables,  on the direct advice of CARDAS engineers to tame a room brightness introduced by a lot of large glass windows.

Tthe CARDAS REFLECTION / CARDAS CLEAR loom was a step-up from my predecessor NORDOST FREY full loom . My experience had an audio performance improvement in MY system ( emphasis added) that’s was not subtle.…full stop.

My take:

= each to his own ….experiment yourself and there is no one-size fits all magic bullet solution IMO … carry on ….

and choose wisely

I am a big fan of Audience Au24. You can pick up the older ones at very fair prices. Works well with Harbeth. I also found Purist Poseidon to work well with Harbeth, but they are heavy and more difficult to work with. They both sounded far better than my Blue Jeans Beldon 10 gauge with my Harbeth P3 speakers. Both Audience and Purist have first rate customer service BTW. 

Duelund. Gig Harbor Audio will make custom lengths and terminations for you.

I would also look into Cardas. Identify an appropriate price range. 
 

I look at wise in two ways: 1) quality (sonically)… overall sophistication of design and execution, and 2) sonic character. 
 

So, as the first attribute gets better… the sound is more refined, less colored… But, that does not guarantee, they will be a positive influence in your system. This is where the system part comes in… why you must try them 

Cardas is one of your best bets because at each investment level they are designed to perform with components appropriately. The generally avoids the problem I have experienced that the wire made the system sound worse.

I agree that cables will matter a lot with these speakers.  Any good speaker will reveal differences in upstream components.  While I have not heard these speakers with either the Cardas Clear or Nordost Frey, I am not at all surprised by the results reported above.  Warmer sounding cables suit these speakers and that is not what any Nordost cable will deliver.  My local dealer usually uses Audio Note cables with this speaker and tube amps.

What can I say, this is if not the nest speakers and true I’ve ever heard is one of the best, reveals everything in the chain.

It really depends on the length you need more than anything.  I would definitely choose the 4s8 over the 4s11, biwire bare connections configuration if possible.

Cheap to try too.