How to identify the S14 ECUs
S14 cars have a different ECU type to the S14a cars - also some S14 cars have an S14a type ECU... The pictures below show the difference.
Here is a picture of an S14 type ECU - notice the 3 blue tabs either side of the central bolt:
Here is a picture of an S14a type ECU - notice the 2 blue tabs either side of the central bolt: