Cables... Its always better to have it a little longer. Amazon Basics will work, but there are better cables... just uncertain about your market.
I use this from Monoprice:
Amazon.com: Monoprice 15ft High-quality Coaxial Audio/Video RCA CL2 Rated Cable - RG6/U 75ohm (for S/PDIF, Digital Coax, Subwoofer, and Compos: Home Audio & Theater
www.amazon.com
If you don't mind a little research... I always recommend avoiding copper-clad conductors (Amazon Basics uses Copper-Clad Aluminum, Mediabridge uses Copper-Clad Steel)... I also like having a good quality insulation and shielding.
That monoprice cable is based on RG6 Coaxial Cable... its a solid copper core, 18AWG instead of thinner gauge in the other cables, and it is double shielded.
That is what I would recommend identifying as a first choice. Hopefully you can find something easily and not too expensive in Europe.
That said, the Amazon Basic will work fine.
BTW, I'm very glad to hear that you are upgrading that sub! I think you will be much happier.
Cheers!