Im not sure actually how unlikely it is. I used to have a Subaru, and so read a lot of threads on Scoobynet. You see this happening quite reguarly - these idiot's buy great big turbo's, whack's them on with no remap and hey presto, engine rebuild time...
Obviously, different car/engine/turbo; but the same principle. Id just take it easy mate and not use too much boost. Better safe than sorry, as has been said.
I was about to say, last time I checked they were different cars, but you spotted that too.
THe pissy small injectors that come on the Ibiza are 'close' to peak headroom on a k03s at 3bar.. so you can take the risk, and hope all your injectors are tip top...