I am considering upgrading my printer to dual Titan Aeros. I have some 3mm filament to use up, but I expect to switch over to 1.75mm. If I buy one 3mm Titan Aero, what components do I need to buy to convert it to 1.75mm eventually? Are the parts available individually, or in one of the upgrade kits so that I can save some money versus buying another complete extruder? I've tried to work it out on my own, but some advice would be helpful.