@larseand - Many years ago I had a a Rega RB250 arm with the standard Rega cable offering.
I upgraded the cable to a Cardas one piece harness into the RB250 Arm and the improvement was most noticeable
I have since replaced that arm with an Audiomods Series III arm that came with a one piece harness and again, the improvements were very noticeable.
So, from my perspective, investing in a very good cable from the cartridge to the phono stage is well worth the expense.
It also allows you to hear any improvements in either cartridge or phono stage upgrades you might pursue in the future with ease.
From my perspective, cables are the arteries of the entire system and without great cables you might as well be listeining to the radio in your car
Regards - Steve