what would be the best amp that does what it says, like as close to exact as possible? or does it mainly depend on the wires you use and the battery and alt?
what an amp can put out depends on whether you can keep the voltage and current necisary to keep it going consistantly. but if the amp is over rated anyway, you'll never see the advertized output no matter what you do. even a great amp won't do what it says if you can't power it. wire too. if the wire is too small, you'll choak the amp basically and it'll fade in and out. so the electircal system is very important.
theres a lot of brands that do what they say or more. i don't think theres any one brand thats best though. JL, Kicker, Xtant, Zapco...are just a couple that do what they are rated for and then some.