Okay, so I just bought an alpine m450 amp (400 watts RMS at 2 ohms) on ebay for around 80 bucks. Which sub would be better for this amp, the alpine type R 12 inch (500 RMS) or the Rockford Fosgate new P2D412 12 inch sub (250 RMS). Its going to be in a sealed box and I'm not going for SPL, but I...