How do I install a AM amp to a Bose Factory OEM car stereo system?

Okay I have a 99 Maxima. I know for a fact that my Bose HU doesnt have any RCA outputs for amp connecting. I have read that a Hi Low p filter could work for connecting a amp. Bose factory Oem speakers runs on 1ohm, which have individual amps, would using a Low P filter work to connect an aftermarket amp and if so correctly, without any risk?