I am about to purchase an amp for my blaupunkt overdrive 15's. They are DVC 4 ohm and take 500 watts rms each. I was wondering what you guys suggest as a good amp to power these. I want to try not to spend more than $300. I am currently looking at the Hifonics zx7500. Its 2x500 watts rms at 2 ohms (i checked with hifonics since there were discrepancies with the specs from different sites). Its only $250 with shipping on ebay. Any thoughts would be great.