I've replaced my AC condenser with an NRF brand unit a week ago as it was clogged and leaking. The AC system still doesn't seal perfectly but holds a steady -28 bar vacuum when we tested it. Good enough.
I feel like the newer gen S3 cooler still won't be enough. Even tho right now the car only makes 300hp, I do plan on fitting the proper S3 injectors and pushing that to 340hp. While it's unplanned right now, sometime in the future, when I'm done with everything I've planned for this car, I may end up forging the rods and pistons to fix the oil consumption issue these cars have and to make the engine safe for more power. I might get a bigger turbo, like one of those BOSS 500 kits. The S3/6R cooler might be too small then.
Regarding lag, how noticeable would you say it is on a bigger cooler? I dont really push the car sub 3k rpm cause it's not a K03 and it's outside of its efficiency zone.
Lastly, would you say you've noticed any improvement during casual driving when it's hot outside? I dont do track days or race with the car, I just do some pulls and floor it every now and then when driving from A to B.