Provided you still have the 16v engine in the vehicle, why are you bothering with bigger brakes?
The size of the brakes are to do with weight of the vehicle. The g60 and mk3s all weigh more than the 16v so got the bigger brakes as they needed them.
By adding bigger brakes to your 16v you are simply adding unsprung weight to the vehicle, thereby making it handle worse.
If you are adding bigger brakes because you're overheating the existing brakes, then simply replace everything for new, and you'll get a much bigger improvement than you're expecting.