In reality their SVC 3 ohm driver are negligibly different from an SVC 4 ohm driver. If your amp will drive a 4 ohm bridged load, it'll handle a W7 just fine...do they do that so you're forced to use their amps? i'm pretty sure most of their amps are 1-4 ohm stable (like the jl 1000.1 takes 1-4 ohms, so it will still put out 1000 rms with 1.33 ohms). if so, what cocks!