Simple as that; so far it had two drastic changes:
1) Cruise speed was reduced to 350 m/s, reducing its efficiency a lot.
2) Cute green "rheinlandish" engine was replaced with a generic bretonian one.
I was mostly curious about the reasoning behind the changes; one of them looks like a matter of balance, another one falls into model development;
but the old engine looked a lot better in my humble opinion - as well as the speed of a Light Fighter hardly turned a ship made of paper with energy-hungry weapons into an "overpowered" tool.