I presume you own the car not a lease (not sure where you stand if you mod the car)
I have had it on my
280 for over 2 years and its defo worth it (and on my car safe). You need to tell your insurance company (it will cost you) and bear in mind it will affect your warranty if you claim on it for engine or drive train.
You should be advised to do oil changes more often (I was told every 5k instead of 10k) and as a minimum you should get some better rubber to
help keep power down and air intake system.
Revo and APR both do reliable maps that give you great power across the range.
Are you also having the stage one DSG map as well as engine.