Morrow Audio Ref 3 or Ref 4 speaker cable??

Need some input from members about Morris Audio's speaker cables, Is their a significant difference in sound quality between the Reference 3 and the Reference 4 speaker cable??. They don't come cheap even with weekly discounts

Also, what model of Nordost's new 'LEIF" CABLES MIGHT THE ABOVE MORRIS MODELS BE EQUIVALENT TO, OR POSSIBLY BETTER.

BTW, Morrow offers a good trade-up policy; however I have read the speaker cables take a very long time to fully break in.