My Engine seized up (oil pump issues) I think the cost to rebuild is pricey, I need an economical used engine, does anyone have a reliable website? I love my 530i help me...

Bought a 2003 530i (e39) for $500 a few weeks ago and I am in the process of fixing it with a friend, but there are a few issues. Any tips on what I should focus on first to get it to pass smog. The car have some water damage as we found water inside underneath driver and passenger seat. It also overheat (change out radiator), but it possible coolant reservoir might still got a leak. Ran the code today and here's what we found : *abs check engine light on *airbag light is on *warning light is on (triangle with the !) *brake light is on 242 Misfire cylinder 5 >check the spark plug, coil, oil in cylinder, injector cleaner?? 123 Electronic thermostat control 10 Coolant temperature sensor 122 Engine oil temperature sensor 209 EWS (electronic immobilizer) manipulation check 53 Idle speed actuator - open coil 27 Idle speed actuator - close coil 100 ECU Self test 37 Switching delay main relay 214 Vehicle speed signal 149 CAN : ABS/ASC Wheel speed signal >change the ABS wheel sensor, but which one? Thank you