you could probably get away with the cheaper stuff if you were just looking to reinforce the chassis so you don't die when you hit the wall drifting and maybe stiffen up the suspension and all of that. BUT, you would just need to accept the risk and understand that it isn't as strong as DOM. I have seen it happen, way too many times. People either throw in a pre made cage, or they fab one up real quick, then they think they are invincible, giving them a false sense of safety, which makes them over confident, then Boom! they are slammed into the wall and on the way to the ER.
there is a right way, and wrong way, and something in between. If you don't need to pass tech inspections, then the something in between will work, you just gotta make sure you're actually designing it right and not just adding steel to look cool.