The 4 ohm speakers may draw more current than 8 ohm ones so larger cable and/or shorter runs may help. I have never seen any difference myself with decent speaker cable but could make a difference in some circumstances.
Speaker Cable Different for 8ohm vs 4ohm
What is the impact on speaker cable when using a 4 ohm speaker such as a Magnepan 3.6 vs a typical 8 ohm speaker. I have read that when using 4 ohm speakers that it is a good idea to keep speaker wire runs as short as possible. Of course, wouldn't it make sense to keep speaker wire runs as short as possible in any case?