Which amp?

I have 2 Infinity Subs 4ohms that run 250RMS. I plan on buying a new amp sometime this month. Im looking at 2 both are Alpines, 1 is 400RMSx1 @ 2ohms and the other is 600RMSx1@ 2ohms. I will be running the subs @ 2ohms. Would it hurt the subs to buy the first amp? Assuming that im not having the amps gain turned up or my stereo so loud it hurts my ears. Or should I buy the 2nd amp?