Thanks wakoko79,
I used an L298 in a paralleled setup (I mean in1 connected to in3 and in2 to in4) to supply a max of 4 amps, but it overheats a lot. It's driving a position controlled servo motor at about 30V and drawing 3.26 amps. That's why I prefer using 4 transistors (mosfets) that way, I can substitute parts with higher rated ones if needed.
I would like using N channel mosfets. I ignore the frequencies being applied (as it depends), but theoretically with the actual setup it can reach about 200,000 updates per second.