This is not subjective. Matching the resistance of a given speaker to the amplifier in use is part and parcel of the function of the system. If you were to run 2-ohm speakers with an amplifier that is not designed for that load, you would eventually (fairly quickly) burn it up, so yes, impedance matching in this scenario is important, it is necessary. It also ensures that you get all you can out of the limited output in a system like this. The Kenwood amp, paired with a 2ohm speaker is a way to get all you can from your investment, and the amp is designed to operate safely at the 2ohm rating. Granted, even at 4ohms, this amp will most likely be an improvement over the stock radio for sure. This is not your run-of-the-mill upgrade. Unfortunately, there are features as mentioned that if you want to retain them require that you get additional information about all the functions and how they relate to the HU, which leads are what, etc. It's recommended that invest in an aftermarket wiring harness that plugs into the existing harness. Crutchfield can help with this. Don't use the BOT, call them!