I have been building stepper systems for the past 24 years. When I got the job to replace the existing system with a G540 and ethernet I had to remove the existing printed circuit board. I was surprised to see that they used the L297 and L298 combo for drivers. I had build several version using that combo of chips Typically the L298 are old bipolar transistors H bridges. They work fine but the surprise is that looking at the current sense resistors indicate that the current was set to 2A. However, the stepper motors were wired bipolar parallel with a current rating of 4 amps. So I was baffled why they would use a 4 amp motor with a 2A driver. Stepper motors current is a big factor in torque. If you wire the motor for bipolar parallel the inductance is 1/2 of a single winding but will yield a higher speed than wired in series. Inductance is the measure of how fast the coils charge or discharge. All I can think of is that they wanted the higher speed and didn't care about the torque.
Dan