You can chip a car, vwoa can detect the chips, and give you a hassle on the warranty if you leave the chip in the car and they detect it. Would suck to blow your motor and be making new car payments huh?
If you get a spare ECU, and a vag-com you can switch them out during service..
The TT225 has a bigger turbo, twin intercoolers, lower compression, and beefier bottom end to run that 225 more reliably.