Hey op and others.
OP needs to check vehicle specs. The M54 motors were not introduced in limited release until 2000 and became widely used in the 2002model year. They closely resemble the m52tu, which was its predecessor from 99ish to 01.
That being said, I have seen m54's in a 92 e30(for those not familiar, that is the factory code for that body style) HOWEVER, that is a custom motor swap.
If it truly has an M54 and it is in good shape, that is worth way more then the asking price IMO.
I would be curious to see a title report on the vehicle as well as information on who did the motor swap because if done well, they are an awesome setup, but if it was a Hack-job in somebodies garage, it could be a nightmare.
Just my 0.02 coins.