Alternative Spindle for a 3040

I intend to buy a Chinese 3040 CNC machine in the near future, probably from carving-cnc (as people seem to be having good luck with packaging from them). I am assuming that I'll need to rewire the machine, and perhaps get a Gecko driver. I'm planning to use it mostly for cutting plastics, tooling board and a few PCBs -- Aluminium would be a bonus, but I won't be upset if it isn't up to it.

I also expect to want to replace the spindle -- as far as I can tell from looking at sellers of spindles of similar appearance, the runout on the stock spindle is probably as bad as 0.05mm. Assuming that the rest of the machine isn't total rubbish I expect to be able to improve its performance significantly with a better spindle.

The two spindles I'm looking at are the Wolfgang Engineering TB-650 (Spindles) and the KL-300 (High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. Automation Technology Inc).

Are there other spindles I should be looking at?

Thanks,
Tom