The Seat's use a CanBus system
The Mk4 Ibiza isn't CANBUS though, but anything based upon the current MK5 Golf platform is.
if it doesn't use the canbus system, why do you need to buy a canbus adaptor as per the one mentioned above in order for the steering wheel controlls to work??? Why have i also been told to get a canbus 2-1 upgrade alarm for my new ibiza???