Well let me just ask you first, are you lights flickering? Usually when that happens, a capacitor is needed. People usually say for every 1k watts, 1 farad cap is needed. That is true, but i usually add capacitors when ever i think is needed.
Capacitors are well worth the money! You should be looking to spend no more than a $100 for 1 farad.
Caps aren't that hard to install. You'll see for yourself when you buy one and read the instructions