I've just brought an ecu with a fahrvergnugen chip allready init, does the chip unlock the ecu and allow me to just plug and play?? or do i need transponder ring and key??

thanks :)

You would need the key chip and immobiliser box from the same car as the ecu is from or you can get your immob and chip matched to your new ecu

These chips are just a tunning chip and do nothing to the immobiliser side of things

oh i see, so what if i took the chip out of the ecu its in now, and put it the ecu thats on the car at the minute? would that work or would i need too flash it in on vagcom or something?

No idea