I would maybe consider something like this Hifonics TXi-6008
http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=6272
Titan series 600-Watt A/B-class 2-channel amplifier
# 1/2-Channel operation
# 600-Watts RMS x 1-ch @ 4-Ohm
# 300-Watts RMS x 2-ch @ 2-Ohm
# 150-Watts RMS x 2-ch @ 4-Ohm
Acouple bucks over budget, but those three letters RMS are important. On at least the Crunch you listed it is listed as peak, which could be three times or even more of what you would actually see.
Ive seen the Hifonics Brutus (BXi monos) listed as a good budget amp so I assume this would be comparable.