x 9081283758132013985737384732834 (carry the one)You do not need a capacitor.
See aboveI think the whole problem here stems from a lack of understanding of the idea of a "system". If you Lego-build it and slap random stuff together, it'll sound like ass and you'll have wasted your money.
If you're smart, however, and you buy things that work well together...the results will be very good.
The same thing applies to engine, suspension, braking, etc. upgrades.