Anyone use this before? Rockford Fosgate Punch P300-10. I am thinking of adding it to my stock system. I also ordered two sets of Kappa's to replace the stock speakers. I don't need to rattle out my fillings, just some more base and better sound from the stock system. I read the kappa's are a nice upgrade. So I wanted more base and something that is an all in one package I can remove easily if need be. I will just tap the speaker line running to the rear subs for signal. Thoughts?