When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It would have to be a hell of a tune but it's plausible. The stage 3 turbo on my car is rated @ 310hp and 355hp running the race tune. I have a much bigger turbo than the one on a GTI so they'd really have to tune it to the ragged edge to get 50Hp.