Subframe connectors

Is .125" thick tubing really necessary? No other chassis metal is that thick, just seems to like a lot of extra weight that will add little torsional stiffness. Also, why 2x3 if you aren't going to have the 3" dimension vertical?

I am planning connectors for my Barracuda shortly and I was going to uses 2x2 tubing with a whatever is availblke in the .060" thick range.