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…
Porsche do manage to instantly date their pre facelift cars, especially the 911. Love the 997.1 but the .2 somehow looks a lot fresher despite such small changes. Same with the 991.
Don’t like what Audi did with the B9 A4 facelift, the pre facelift car still looks better. I didn’t like the 8V A3 facelift to start with but do quite like it now