Sourcing the correct spring, really only one way to be sure of replacing "like with like" and that will be to buy the correct VW Group part, your springs will be marked with colour "splashes", note the colours and the number each and someone will get back to you with the current part number.
Disconnecting and reconnecting the lead on the adjustable damper should not cause any problems.
Maybe consider replacing both front springs and so both top mountings, bearings, thrust washer and all bolts and nuts removed - including the piston top self locking nuts.
Get alignment checked after completing this job.