I used this Amp in my Mazda with aftermarket speakers and it sounded phenomenal. I never used the amp at max peak power because of how well it amplified my speakers.

I no longer have the car and I am not going to use this Amp anymore.

4 Channel Amplifier

CX300.4 Specifications

RMS Power@ 14.4V, 4Ω stereo, ≤ 1% THD+N : 40W x 4

@ 14.4V, 2Ω stereo, ≤ 1% THD+N : 75W x 4

@ 14.4V, 4Ω mono, ≤ 1% THD+N : 150W x 2Length [in, cm]12-7/16, 32Height [in, cm]2-3/8, 6Width [in, cm]7-3/16, 18Frequency Response ± 1dB10Hz–20KHz

Signal-to-noise Ratio>95dB, A-weighted, re: rated powerInput SensitivityLow Level: 125mV–5V

High Level: 250mV–10VElectronic CrossoverSelectable: HI, LO or OFF; Variable 50–200Hz @ 12dB/OctaveBass BoostVariable 0–12dB @ 40Hz