I figured out what the connector is for the S5 BAC. This should benefit anyone that wants to rebuild their engine harness, because I didn't see anything relevant on this site. After comparing the connector to the S5 injector connector I noticed that it was remarkably similar except that the tab on the sides was in different locations. I started searching for "Nippon Denso connectors" and found that the S5 injectors are a Nippon Denso top slot connector and the S5 BAC looked like a Nippon Denso bottom slot connector. The dual slot connector can be used with either and is what I purchased.

 

Thank you so much for this find! I was having the so much trouble with this connector. Where did you purchase it though?

 

I bought it on ebay.

Fuel Injector Clip Miata WRX STI 350z Supra Camry Corolla Celica GS300 IS300 RX7 | eBay

 

I just got mine in yesterday! did you make any alterations to it as far as the locking tab goes?

 

No, I thought I might need to file off the two tabs on the sides of the locking tab, but slid on and latched securely.