I have a few aerostruders that I converted to 1.75mm
The biggest issue is that the titan aero for 1.75mm filament is shorter than the 2.85mm version, this causes the fan shroud to collide with the bed leveling washers.
What you need to do is modify a 2.85mm titan and drill out the heat break threads with a 6mm drill bit and then run a m7 tap through it. you have to be careful and keep checking how far the heat break goes in. you want the shoulder of the 1.75mm heat break to be level with the bottom surface of the titan. You also need to drill out the hole on the top so that a piece of pfte tubing can pass through from the heat break to the filament guide (i’m not sure what size I used) after that you just need a 1.75mm filament guide that comes with the titan kits and a piece of pfte tubing and trim to the right length (I don’t remember how long that was either)
If I get time I’ll make a thread and post my pics, I have found that I get higher quality prints and higher speed with 1.75mm filament on the aerostuder.
I’m not sure about cura but in simplify3d all I had to do was go in the advanced tab and change the filament size from 2.85 to 1.75