There are metal replacement parts for many of the traditionally PETG 3D printed parts for the Mk3 available online.

We are not yet aware of anyone who has done an objective test of these (measuring tolerance vs spec, measuring flex or vibration etc), so these are not yet recommended.

However links to these parts are below: -

[Aluminum Y-axis rod holder/clamp](https://www.aliexpress.com/item/4pcs-Prusa-i3-MK3-Y-axis-smooth-rod-holder-clamps-black-anodized-aluminum-rod-front-rear/32861668476.html)

[Aluminum Y-axis belt holder](https://www.aliexpress.com/item/1pcs-Prusa-i3-MK3-black-anodized-aluminum-alloy-Y-Belt-Holder-for-Reprap-Prusa-i3-MK3/32876552268.html)

[Aluminum Y-axis motor mount and idler end](https://www.aliexpress.com/item/aluminum-alloy-Prusa-i3-MK3-3d-printer-Y-end-motor-holder-and-Y-end-idler-kit/32879217205.html)

[Aluminum X-axis motor and idler ends](https://www.aliexpress.com/item/-/32879096023.html)

[Aluminum Z-axis mounts](https://www.aliexpress.com/item/1set-Prusa-i3-solid-fixed-Z-axis-mounts-kit-with-8mm-bearing-for-TR8-lead-screw/32854324917.html)

-> I would not recommend those Z tops with bearings. the lead screw should not be constrained, only the smooth rod.

Note that for other brits out there, it's ok ... Aluminum is just how those American folks mis-spell Aluminium :)