With a 10:1 transformer you don't need anything fancy, a normal audio power amplifier will do fine. The impedance ratio is 100:1 so a .25 ohm driver will look like 25 ohms. 6:1 would be better and works give you about 8 ohms.
A transformer is the easy way to go but direct drive is certainly possible if you are custom designing the amplifier. Some subwoofer amplifiers are designed to be stable down to 1 ohm loads. they are intended to drive parallel 4 ohm voice coils in bridge tied configuration. Basically you need parallel output drivers, current feedback, low supply voltage and an auxiliary supply for the gate drive.