The continuous torque is 3ft/lb so approx 4Nm.
You really want to keep the torque about the same or more than you have now as I would imagine the manufacturer sized the motors accordingly. Having said that I have seen some massively over sized motors on older machines.
You could get smaller motors with more RPM and gear them so that the Torque increases, whether you would manage that would depend on whether there is room on the machine to gear accordingly.
I like the CSMIO/IP-A better than the IP-S because the DROs in Mach get updated from the feedback to the CSMIO/IP-A from the motors encoders, so Mach always has the correct position.
If using the IP-S then you are just reading where Mach thinks the axis is. In reality that should be the position or very close if the servo drive is tuned correctly and has a small fault value set.
However with the IP-A you are always sure, also after an E-Stop or even winding an axis by hand, Mach knows where the axis actually is.
The major benefit to me however is, as long as the drives logic side is enabled, then the encoders data will update Machs DROs, so you will not have to home the machine each time you disable/enable the servo drive.
So for example you disable a drive, the axis will move slightly due to gravity, belt tension or whatever, how much it will move will depend on the forces acting on it. A Z axis could move quite a bit until the brake catches it. When using the IP-S you would have to re-home before using but with the IP-A Mach has seen that movement so you just need to enable and away you go.
Hood