Hello,
Running mach3 on the machine with geckos would mean a gut job on the electronics and motors.
In my opinion, replacing servos with steppers is a huge step down in quality and reliability
If you're the person I spoke to by email yesterday, I think the odds are good that it will be simple to get the machine running as it was intended, let's give that a shot first and see how it goes. Could be as simple as a fuse.