I've done two front wishbones on my S4, both were from landing at daft angles on a high(ish) drop off section, ended breaking into about 5 or 6 pieces. I know I should have learnt the first time not to jump off it
I noticed on a well known auction site you can get delrin ones from the USA for a fairly reasonable price. Whether they are any stronger or not I don't know, but they do look a bit beefier.