SiFab offer full stainless exhausts bobbins for 4 wheelers as shown below. Around £3.50 each.

[Linked Image]

You would need to check if suitable for M3W but rubber part is 30mm dia. x 20mm height with same M8 studs. Mine failed due to rusting of the metal to rubber interface which destroys the bond.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone