PrimaLuna Evo 400 and Kanta No. 2 - which cables??

No such a thing as “best”. My best in my system will be different than the best in your system.   How much are you looking to spend?  New or used?   If you want excellent sounding but very inexpensive cables, look at Blue Jeans Cable LC1 interconnect.  It uses quality Belden cable and very good RCA connectors. A 1 meter pair is most likely less than $50.00. 

What is your budget? I am running Purist Audio cables with my PrimaLuna EVO400 and Sonus Faber.

"best speaker cables to compliment"

Off to a bad start with good equipment. Highly doubtful anyone qualified to tell YOU what's best for YOUR ears?

Buy from a known brand in your budget. Room/location should have more impact than cable. 

What frequency is lacking in your system where a little boost might help?