I have to agree with Moper watch this video no other explanation needed. Look at the way the front bars absorbed the impact because of the arc built into them. This cage was properly engineered and no doubt save this girls life .
Your Bars on impact would probably rip the through the cowl without much force. Come back through the windshield bounce off the inside of the a-pillar and probably take your head off. Just a thought for your safety. Steve
Watch this video
http://www.youtube.com/watch?feature=player_detailpage&v=X06VSud3I38