http://www.bestbuy.com/site/hifonics-hercules-class-d-digital-mono-mosfet-amplifier-with-variable-low-pass-crossover-black/5201009.p?id=bb5201009&skuId=5201009&productCategoryId=abcat0302003

And to get the most clarity on your sound system you most likely need to get new mediums, depending on what car you use, something i would definetly recommend is that you get a capasitor just to save some battery.

If you decide to get the mediums, try to get the kickers, also a nice equalizer and a crossover bass adjustor just to balance all your sound. For your stereo i would also recommend hd quality. Hope i help, enjoy.