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…
MK7 Golf R looks better with a facelift. I have a pre-facelift R and the square-shapes in the headlights & taillights, in my opinion, look worse than the facelifted designed that feel more streamlined.