Bi-wireing Proac 2.5

I would like to know if anybody has any personal experience with this speaker. What are the sonic differences if any between the normal vs. bi-wire? Did you get the chill factor? The difference in price is quite a bit to bi-wire and if it's not the chill factor,goosebump type of difference I don't know if it is worth the extra cash. Any ideas is greatly appreciated. Thank you, John