Sadly M3W production numbers are not up there with VW Golfs, Ford Focus or even Lotus Elise and poly bush companies are not that interested in satisfying a small market by producing bushes in the correct size. They don't match up well with anything else either. If you can find some poly bushes in the correct spec, please let me know and I will be inline for a set as well. When I fitted a set to my Elise they made a big improvement, even a fraction of that on the M3W would be great.
There are some smaller players out there that may be interested
eg,
https://batchpoly.com/What you really need is someone to invent poly rod or granules for a conventional 3D printer
