Do i need to use the idle speed motor connector that comes off of the ECU connector on the E8? Is it needed?

Also my car is a FD3S

 

No.
The FD3S stock idle control use a BAC valve so you would need to use one of the PWM outputs from the E-8. The BAC use two wires one from the PWM output and the other from a switched 12v ignition.
The idle speed connector on the E-8 is used to control stepper type idle motors or 4-wire types. On the FD3S you can use the idle speed connector to control the oil metering pump if you wish too.

 

thanks alot.