4130 tubing is available in different conditions. SFI specs call for Condition N or normalized for anything used in the structure of a chassis. Sheet is also available in Condition A or annealed which is not as strong and easier to form. There is also a hardened material that was talked about a number of years ago after some well publicized problems but hasn't been talked about for awhile.

Years ago I saw a car that wrecked hard, came apart and hurt the guy pretty bad. Nothing was bent, everything that came apart looked like broken glass. And this was not a backyard car. You have to pay attention to this stuff and where it comes from.