I don't see a problem with this at all, as long as you had proper welds i don't see why it would fall apart. Did you guys know that the actual weld is stronger than the metal that was welded. If the welds were done properly, then you have nothing to worry about.

its like saying those guys who build the locosts shouldn't race those cars because they welded their own frame, that's ridiculous.

if you feel you did a proper job welding it, then you have nothing to worry about, and i see that you did this method because the car looks to have been wrecked in the front, i think you did a good job.