Had 2 different lowering springs so far on my Cupra.
First had the VW-Racingline springs (front -30mm and rear -35mm) the ride quality was very good and their were suprisingly smooth and good at cornering. Had to change them due to missing TUV certificate/Certificate they fit the car (bad
service at racingline as they did not even have the decency to answer my enquiry) so I could get my car Yearly Inspection done.
So I changed to H&R springs (front -35mm rear -40mm). The stance is better and the car looks better. Ride quality is harder, but they take in bumps better than the racingline ones. Cornering is a little better and dynamic.
I have the Racingline springs in storage (driven around 5000km) if anybody is interested