I'm redoing the audio in my '07 Mazda3 Hatch and I'm not sure what interface I should get for it. I want aftermarket sound without replacing the factory unit because it just looks so **** good. I was looking at the MTX Re-q5, but I'm worried about alternator hum because the outputs are less than 4 volts. Also, I'm not looking to spend over $120. This system is going to be all JL if that means anything.