I have a standard GTi and wanted an edition 30 splitter. Every one I saw on marketplace/ebay from a car being broken for parts was battered (to be expected tbh as they're older cars now). So I would advise buying new and getting it painted, luckily black is easy to colormatch so you'll be fine on that front.
If you want to save money do what I did and buy the replica one from ebay (around £120) and paint it yourself. I did mine with 2K clearcoat aerosol cans and it turned out great. Fitment is spot on but I'm assuming it's not going to be as tough as a genuine VW one. They are really easy to fit, just a couple of torx screws. If you get a replica make sure it's made out of Abs plastic and not fibreglass as they can
be hard to paint and prone to cracking.