. Keep some slack in the cables for future experimentation with speaker placement.
Speakers don’t have a wattage, The specs for these speakers say compatibility with 25-100W amps. That doesn’t mean you need 100W amp. A 60Wx2 amp can be sufficient, even a good quality 45Wx2 amp may suffice. But as some others have said, there might not be a need to change your current amp.
Try upgrading the speaker cables for further improvement. Will cost far less than upgrading your amp. Belden cables are both affordable and well-regarded. You could even try borrowing better cables from someone in your city to check the improvement first.
Consider investing in an entry level DAC. The Chromecast audio can be connected via optical to it. That should bring in another quantum of improvement in sound.