More Power or use subwoofer to boost bass for music

To enhance bass you need to try to position the speakers closer to walls to amplify the lower bass, or add subwoofers. The answer is not adding multiple subs or adding bass absorption. The rational approach is to start with proper imaging using a method such as The Master Set. Imaging is key to proper sound from a stereo source. Once the imaging is perfect you can then add subwoofers for the lowest frequencies if you want more bass. It may help to use a computer and microphone to real time analyze the frequencies in your room. Then you will know how far down your speakers go. If you want 20 Hz or below you will need subwoofers. They are tricky but to get 20 Hz and below you have to move air. Lots of air. You will need 15” woofers. The idea of a “swarm” of subs is based on evening out the nodes. It’s an admirable goal but rarely practical. One well placed sub is good but not easy or perfect. Two well placed subs are better but beyond that you are spending a lot to get a little. Like horsepower. Look up Harman Kardon white paper on sub placement. Seminal work. Proper placement of stereo speakers doesn’t necessarily mean the proper placement for bass or subs. I recommend Hsu Research or SVS for affordable well made subs. That way You can afford two or three. Hsu sells pairs of identical subs. Best of luck and keep us posted. 

In an attempt to be helpful to the OP I want to present the research data from Harman regarding multiple subs. The research is extensive with computer modeling and multiple variations in numbers and placement. It’s easy find online and well worth the reading. Multiple subs are not a cult but are scientifically proven to even out bass nodes but are they really necessary?  Where do you want to spend your limited funds?  Here is their conclusion:
” Four subwoofers are enough to get the best results of any configuration tried. Two subwoofers is very nearly as good and has very good low frequency support as well.”

The midrange is where most of the fidelity in reproduced recordings lies, in my opinion. Proper speaker positioning and an excellent midrange would be my first goal. If money is left over considering amplification, room treatments, cabling and two matched subs, then get two more. But as their research shows you can do very well with two high quality matched subs.