Changes rods for linear rails I would like to know if it is possible to change the rollers for linear rails, just replacing or some calculation should be done and take some precautions.

In my case,  I have a Core XY DIY printer.





I was reading about need to migrate of 8 Bits to 32 Bits, because for get better resolution, results and should be update more things, like add autolevel, etc.
I've seen mods for the Hypercube (and Hypercube Evolution) using linear rails (e.g. this mod), so yes that is possible. You need to redesign a few parts and make sure you have the correct length, but that shouldn't be too difficult.