Correction. It is the 150.1 and it goes for maybe alittle over $100 shipped. If he only has one sub that handles maybe 180 RMS 300 MAX, why would he get the 300.1? JBLs 150.1 will be dead on. JBLs 300.1 will be good for two of those subs.
Whats the impedance of the sub? I say go 300.1, because if it is able to be wired to 4 ohms, thats 160-170 watts, and you can always add on another sub and wire it to 2 ohms for 325 watts.