[Apogee]

I would personally use DOM mild steel over chromoly unless you're planning on post heat-treatment at the weld zones like duece_454 pointed out. There was a big fuss a few years ago about mandating chromoly cages in some of the SCORE desert classes which boiled down to the cost versus safety...the debate was about whether a chromoly cage is really safer than a DOM cage. Racing is an inherently unsafe activity, however nobody wants to pay more for something that doesn't definitely improve the safety of the rigs and/or give them some competitive advantage.

While there's no doubt that chromoly is stronger for the same wall thickness so long as it's welded properly, the debate centered around how rigid you wanted your cage to be? Cars have crumple zones for a reason and that's to distribute the force of an impact over a greater period of time since the impact is typically what does the most damage to the soft and squishy thing inside called the "driver". I think we can all agree though that once a crash begins to occur, the "driver" is really a passenger at that point.

Tobin