@gianakop It depends on what other printers you have on hand. In my case, I bought the creatr for $150 off someone on Craigslist. I tried to get it to a good working state but was never able to get decent prints off it. So, I parted it for parts to upgrade my Tronxy X5sa Pro.
The glass plate worked perfectly for the x5sa pro. I'll probably use the 40x40 aluminum extrusion to strengthen the frame of the x5sa. First, I have to measure and cut it to fit the x5sa.
@gianakop Just wanted to thank you for your contribution! My leapfrog nema 17 motors were missing the model number stickers so I was never able to look up the specs. I'm tearing down my unreliable Creatr and will be using it's parts to upgrade my incoming TronXY x5sa Pro that will arrive in a couple days.
Anyways, I registered just to add to your info what I've found about the nema 23 motor.
http://www.multiprojekt.ro/produse/motoare-pas-cu-pas/motoare-pas-cu-pas-stepper
So my guess would be
SM = stepper motor
57 = width of motor
T = most likely "Torque"
56 = length of motor
280 = 2.8 a
4 = 4 wires
A = 1.8 pitch single axis
You can also refer to this pdf for future motor references.