HMMMMMM, someone that knows what's going on in the car stereo world - I think caps are BS because they only are a patch for too thin power wire. They DO NOT at all help with alternator output voltage stability (aka lights dimming). All a cap does is "stiffen" the powersupply to the amp (which has smaller caps built in to it already) kind of acting like a small battery, but it won't "boost" your charging system voltage - in fact everytime the cap gets discharged it has to get recharged, which requires current on top of what the amp is drawing. The only way to fix light dimming issues are to upgrade your wiring and to install a higher output alternator - no ifs ands or buts about it. I have two rockford amps in my car that will draw peaks of 120 amps when played loud enough, but I don't have a cap and I don't need one b/c my wiring is beefy enough and I have no light dimming issues b/c I run a modified accord alternator that puts out 150 amps at 1500 rpm - enough to cover the system and the extra load from the rest of the car. The one and only thing that IMO justifies a cap is that it can reduce noise a bit from the charging system from the car - that's just about it! Spend the extra 100 bucks on thick wire!