Removing the bumper supports??
The bumper supports don't weigh much. If you are going to do it just remove the entire bumper with the supports attached. They are not needed. You can't tell if they are gone. (Front and back.) If you get in an accident you will do more damage to the car. That's the only real "con" to this venture.
If it's a street car I'd leave them in. I've done all kinds of weight reduction on my car including removing HVAC, PS, ABS, Wiper assembly etc. plus $$ mods but I do drive it on the street and I kept the bumpers in, just in case ya know.


