1020 DOM tubing is cheaper but better, Not even close. 1020 does work for a street chassis. most all race chassis are chrome moly for a reason., it is about 4 times stronger and stiffer then 1020. properly made welds are much stronger and easier to do on chrome moly. the NHRA requires that all roll bars ( mild steel or chrome moly) be certified on 9.99 sec or faster then 135 mph cars every 3 years. mild steel bars are required to be thicker then the chrome moly ones because they are not as strong. try bending some tubing in a hand bender and you will get an appreciation for how much stiffer and strong the chrome moly really is