I run a cap only because my new setup came with it. My old setup i was running was a 900 watt amp, with two 12 inch kenwoods and it would dim the lights pretty dwecent when they hit. The new setup is a 1300 watt kicker amp with two 12 inch sonys and witht eh cap installed i deffinately notice the difference int he dimming. Personal preference but if you have it, and you feel comfortable putting it in and running it then go for it. Im just one person but im satisifed with mine.