Should I upgrade my speaker cables?

I wouldn't.  18 lines of gauge 22 is area equivalent to gauge between  9 and 10.  Resistance will be in order of 1mohm/ft.  20mohm (both ways total) of 10ft cables is very low.  Yes, it is creating divider with the impedance of the speaker, but it is the same divider no matter what delivered power is.   Are you afraid of overheating the cable?  Even if you run 12A causing 3W power dissipation in the cable it is only 0.3W per foot and it is peak power. Dissipated heat is a function of average power, that for music is very low - perhaps the highest for popular music at about 7% of the peak power - making here 20mW per foot.

i agree, welcome.

I would say it is likely you can improve the sound of your system with a different choose. Not so much because of the change in wattage… more in terms of a cable upgrade. My experience is that upper end Nordost are really good sounding… not so much the lower tires.

But it isn’t entirely a question “of better”, more a question of sounding better in your system… but also higher quality. You need to find ones that make your system sound better… typically the only way to do this is try them. If you think your system sounds perfect… then you will not be looking for a warmer or more crisp cable. But you still might find that one or the other helps. You might try a high end Nordost, Audio Quest, Transparent, Cardas, and wire world. These have huge advantages of being widely professionally reviewed so you can get an idea of their characteristics before borrowing some… then help to make further choices. 
 

You need to make sure any you try are broken in and you listen to them a lot as you want all the nuances to be positive to you. Not just have them sound more detailed or have more slam.

Try lending library at the cable company.

Thanks 

Check with a local dealer. Often demoing cables is a lot easier than equipment. Good luck and let us know how you make out. 

Heimdal2 is not a low tier model, it is the low end of the higher tier Norse2 series.  As such, it uses the same materials and tech as upper Norse2 models.  You don’t say how long they are…it matters.  Kijanki spelled it out…he must be a physicist…so if your speaker wires are under 3M I’d say you are getting what Nordost has to offer.  You can try some Transparent Ultra or Cardas Cygnus if you want a mellower balance, at the expense of $$$$ and maybe a little clarity, or as the Bris call it, insight.