I used it for one year with very good results, I suppose you can find this spring in USA.
The feeling is a bit better than the foam I put there before the updated spring and it's close to the feeling of my CSR elite pedals (load cell brake).
I had to cut a bit the "cross" shape that is inside the G27 red container of the spring because the spring was a bit narrow, if you don't want to cut the plastic you can put there a coin over the cross shape as a base for your spring, I suppose too the spring will be stronger to press as it'll be a bit more compressed.