don't know about the reg, I think I read someplace the difference tends to be a couple few pounds, I can't imagine it's worth the cost of a titanium reg? I considered this at one point and came to the conclusion it wasn't worth it, especially given the whole nitrox/titanium thing.
what all are you packing that you are over, and what are you packing in? Or are you on small planes a lot where the weight limit is lower? Maybe there are some other ways you could save weight. I'm sure some people go over, but I think most people do manage to take their dive gear, clothing and other stuff, and often camera gear and laptops, and stay within 2 50# checked bags each plus the carry on stuff.