I’ll start with the Porsche 997, the 996 looked alright imo, but it looks “like a 90s Porsche”, the 997 made it look sleeker and more modern. Still looks good today.
As for cars that looked worse after a facelift? Maybe the facelifted 6th gen Camaro? The 6th gen looked great pre-facelift, but they did something weird with the headlights and now it looks so-so…
That ugly chrome stripe in the E90 kidneys is hideous. Luckily they facelifted that away. Only problem is that if you have a prefacelift car you not only have to change the kidneys, but also the hood.