Part it out. Every penny you've dropped on mods or repairs becomes worthless when selling it. A friend of mine had a heavily modded E46 M3 with 45k miles on it. He had it on the market for a year before parting out. Once he did that, the car sold fast.
2005 M3 6MT | Weekend toy & Track rat
2003 330i ZHP 6MT | Wife Mobile
1994 325i 5MT | DD