I spoke with a guy who is very knowledgeable in building race cars and he spoke to me about "peening". Apparently it hardens the metal, makes it stronger and less prone to cracking. He specifically said doing this to springs is a good idea.

http://en.wikipedia.org/wiki/Peening

Does anyone know if there is truth to this?

 

Its more commonly called shot-peening, it leaves a compressed layer of metal on the outside of the part which is less prone to cracking. Sure its a good idea on springs, sway bars etc, but unless the part is fatigue limited (most steel parts are not) its not going to gain you anything. I wouldn't waste your time on it unless you've got parts that are failing already.

 

What about on Cromemoly?

 

a fix for a non existent problem

 

Awesome. That answers my Q's. Cheers!