if you were to do it then the front lambda would be fine but the rear would need to be simulated or the ecu flashed to remove the rear lambda output or increased thresholds
from my experience in decat's you have to be careful with the flow and back pressure on the rear components like the centre silencer and back box
my calibra ate through centre sections with a decat but i didn't want a racing tube otherwise it would be stupidly loud and raspy
so if u were to decat then get a performance catback such as magenx that put 2 silencers on the centre section and baffled backbox
qwuikfit centre sections will last 2 months