It would be hard to value a car without pictures of the exterior and interior. Also it's just around that time where if someone bought it, it would be time for a rebuild of the motor, which as you probably know wouldn't be very cheap for that motor. A very generic evaluation just based on the fact that the S38 is in there, would be the $10,000 you stated.
1987 325is(Midnight Tuning Tuned OBD I S52
) - Current Summer Car
2012 Hyundai Veloster Tech- Daily Driver
1985 318i - 1st Car (started it all)