edit: I put a 10,000uF cap in and it helped by a noticeable amount. I can get about 10 more of these pretty cheap but my concern is this: if I put say 10 capacitors in parallel do they need balancing? I've read this and that but I can't dig up a definite answer.
Capacitors don't need any balancing (whatever you may have read), as long as they're connected together, they cannot be at different voltages, so they're self balancing you may say.
Add 1 or a few at a time, and keep an eye on the start up surge (and the punch in the low frequencies of course, no need to add more than needed to cure the lows).
A large capacitance looks like a short circuit to the power supply at start up - you may even need to add a soft start circuit.
Suitable PTC resistor(s) would do the trick. A power resistor that is shunted by a relay when the caps are up is another common solution.