Its the ECU that controls the actuation of the Air Bag and also the seat belt pre tensioners on the std seats, if you have removed both of them yes you can remove it, but you may also have to take the Air bag light bulb out if it stays on but im 90% sure it won't as you are taking the ecu control box under the rear seat out etc.
Cheers Dave aka Daishag Rallying 07805835655
P.S. there might be a problem here for all of us that have done this as there is a potential rule change for MOT regulations for 2012, as to include a correct functioning srs light (airbag warning light) for cars made after a certain date or cars originally made with that option.

