Kicker KEY5001 500W Mono Car Amplifier with Bass Revealer Processor - Smart Amp for Enhanced Audio Performance | Perfect for Car Audio Systems & Bass Enthusiasts

I was immediately let down the by original 4" sub that came with the "premium" Bose audio system, but I didn't want to start cutting wires on my brand new car. I wanted to use the original subwoofer signal, but I also knew that Bose was pulling a few tricks to roll off the bass output in order to protect their tiny little subwoofer from blowing itself to shreds.The amp is small enough that I was able to just carve a recess for it out of the foam piece in the trunk, so it's completely hidden and protected. I was actually able to make a little harness that plugs directly to the original signal wire and take it to the Kicker amp rather than the Bose subwoofer. With this, I can actually unplug the amp, remove the sub from the trunk and plug the original Bose sub straight back in without any further fuss. It also works out well because the 4th gen Mazda 3 doesn't have a single fuse that is switched with the ignition, so running a remote turn-on wire wasn't an option. However, with the high-level subwoofer signal going into the amp and DC offset mode activated, it turns on and off perfectly, no remote wire necessary.The signal processing done by this amp is perfect for being attached to the Bose system, again, because I didn't want to go tearing the car apart or cutting wires to reach an unprocessed, full-range signal in my brand new car. The setup process for that took me a few tries to get right because THERE ARE NO INSTRUCTIONS IN THE BOX. I was trying to follow along with youtube videos from memory. And then I also kept forgetting to get the car's stereo set up correctly before I started, which that one's on me... Once I looked up and printed off the instruction PDF on my own though, it was pretty straight forward. However, there are multiple sets of test tracks and they don't really specify which to use. I originally started with the -0dB set, and that ended up feeling pretty weak. But after reading the instruction for how to do a factory reset on the amp, I redid the setup process one last time with the -5dB test tracks and it's absolutely perfect now.I did have an issue with the Kicker CXARC remote volume knob though. The cord that it came with wouldn't click in deep enough to the hole on the amp, so I had to buy a different cord that was narrower near the jack itself. So it's already disappointing that the amp just doesn't already come with the remote volume knob, and even more annoying that I also had to replace the cord for it, meaning that to get a working remote knob for this amp, it's basically an extra $55.Also note that the power terminals on this amp aren't particularly big. I thought I'd play it super safe by using a 4AWG wiring kit, but the terminals only fit 8AWG wire, so that was basically just wasted money.