These cars have started getting pretty cheap. It still seems a bit too low, so I'd recommend that you ensure you get a CARFAX and have the dealership or a BMW mechanic you trust do a pre-purchase preinspection (will cost you ~$100). The dealership should also be able to run the VIN history showing any maintenance done by any BMW dealership while under warrantyand since. Also ask teh seller for maintenance records.
Otherwise, ether is nothing in particular about that year that you should be running away from. 2004 was the fifth year of the E46 coupe, and the fourth year for the 325Ci, so the kinks had been ironed out by then. Also, you get the facelifted front, which is much better looking than the early coupes in my opinion.