I use a lot of 16 gauge. I have even been looking at some 18 gauge for the lighter motors.

Foam bumpers weigh roughly 4 grams vs. the substantial amount the kydex weighs.... which will change up the car's handling. Kydex bends too, just depends on the impact.... but does not support the body or prevent post hole tears. It's hard for me to be unbiased since I sell 3 colors of foam bumpers.