As MarkB pointed out, round tubing is much stronger and lighter than square tubing. It looks more professional and business like in my opinion
(others may differ) and looking back, wished I built mine with tube...
However, here are some pictures of a frame build by my friend and still under construction at this stage, and rest assure that frame is as square as can be. As a matter of fact, they build these things as part of scraping together a living.
The engine is a 20V black top 4AGE and the diff a Subaru unit
