Welcome to the forum Michael, you'll find the members on here are a friendly and helpful bunch :)
You'll have a lambda sensor on the exhaust system to help the car monitor the emissions. This could be affected if you have a decat.
I see you live in Ireland and I'm assuming you live in the republic of Ireland in which case this won't apply, but.....
If you live in the UK there are now stricter mot regulations regarding emissions which come into force in May.
Cheers
Steve