Paralleling 2 subs does not neccessarily rquire a bigger amp. When you parallel 2 4ohm subs the impedance drops to 2ohms. Most amps IF the can handle a 2ohm MONO load will roughly double their output. Meaning your 200w@4ohm amp will now put out approx 400W@2ohms. You should be more concerned over the distortion (THD) and slew rate (>1000) than total output. A good clean 100W amp will sound louder than a 400W piece of crap. What are your goals for your system? Are you looking for clarity, volume, or both? In today's market you can get it if you pay for it. IF you have more questions jeffrey_scoggins@tvratings.com