Recently 2 of E90 Carbon Leather trims were sold for $650.
One set was mine and another member sold it as well for same money. So I think you can get about 650 out (even though E92 trims are a bit more expensive than E90s).
You will get some bites over E90Post side as well so post there too.
PAST: 11 E70 X5M | 08 E90 M3 | 08 E92 335i | 03.5 E46 M3 | 99 E36 M3