Looks like a nice project. My 3D printer uses M8 threaded rod, it works surprisingly well considering the price. I have always had doubts about the accuracy, but when printing at a resolution of around 0.1 mm it is not critical. The bigger problem I have is "wobble", although I think that is more of a design issue with the printer frame.

Unfortunately, the price hike to leadscrew is pretty steep. I priced up 4 sets of 10mm leadscrew and it was way too much. I would be better putting it towards a new machine.

A couple of questions: how is the wire tensioned? Presumably it has some stretch to allow for change in distance while it is cutting a profile?

Is there anything special in the software setup to handle the fact you effectively have two X,Y coordinates? My understanding of the GCode machine model is that all axes in a G1 move are synchronised and coordinated, so it does not matter how or where the axes are.