Lower front arms - what's the diff between them?

[kidcongo]

Can anyone explain the difference between these three front arms that fit my TRF buggy? I understand one is hard, one soft, but what is the third? Which is least likely to break?

51275 Lower Arm
51283 High Traction soft lower arm
51141 High Traction lower arm

They are all listed here at the bottom of page 4 from the TRF502X:
http://www.jtmodels.co.uk/