I did bend my servo plate slightly once, it was only minor though so a few bashes with a hammer and it was flat again- Ti skid saved my bacon.
As for replacement parts, ebay or B/S/T sections for originals, otherwise its a case of making a copy of the originals yourself by sending them to a machine shop; thats a rather $$$ option though, so my better suggestion would be to hit-up a fellow forum member. In my case, that would be the Candyman as he's UK based like me and has mad-skills, or you USA dudes could try either Metalman, Monster Mike, or maybe Serum (there are probably a few others too, just a case of finding the really nice custom built vehicles vs straight-forward kit based conversions etc).
Stronger X-braces are on my wish list though, just depends if or when I find another set of concrete steps to crash into...
Ti is lighter than Alu in principle, but I think it depends on the specifc type/alloy, and thickness ofcourse- seen some types of stell that are lighter and stronger than Ti, so it isnt the uber metal that some guys make it out to be all the time (for our needs though its plenty tough enough).