If i don't have my headlights on high beam, they are much dimmer. I compared my headlights (highbeam off) with another and it was dimmer. What could be the problem? I heard it was because I used to have a system without a capacitor and sucked a lot of the power from the alternator. Could this be the problem?

 

how does the car start?, does it start right up or slowly crank over?, could be your battery dieing or your alternator taking a crap on you. Test the alternator at any local parts store, and if need replace it with a more higher output alternator.

 

Or your lights could be OEM from 94 and tired. The car you are comparing yours to may have new halogens which indeed are brighter.
Clean the lens if dirty....make sure the plug on the back is firmly seated on the bulb.

Buy new light bulbs and do one side to see if it is brighter.