I've still got the stock bumpers and stock bulkheads, and the only thing I've ever broke in that area are a couple of bumper supports. the stock ones are pretty weak, and that's why I still keep them, because they give so much. I run the mess out of my Maxx, slamming it into trees and landing nose down and ass end up, and the stockers seem to take the hit pretty good. Hey, it's kind of funny, but the stock bumpers are about the only thing that have taken constant abuse and not broken yet.
So, whatever you get, listen to what Christain said about them being there to take the force of an impact. I suppose titanium bumpers would be ok if you maybe used RPM supports. But if you've got titanium bumpers and aluminum supports ect ect ect than the hit of the impact has to go somewhere, and it's going to keep going until it finds a week spot.