Ti vs Steel frame

[deluz]

I am contemplating a new custom frame.
I already have one made with 853 Pro Team OS tubing and love it.
The goal of the new one would be to make it a bit different and lighter by using TIG welding and a carbon fork. I realize the weight savings is going to minimal.
The new frame could be a light steel like Columbus Spirit or Ti, with Ti obviously costing more. I read that Ti has half the weight of Steel but also half the stiffness. So to make a frame with the same stiffness, the same weight of material is needed. But it seems that Ti frames are lighter than steel by about 1/2 pound. How is this possible? Are Ti frames less stiff than steel?
I read that paint on a steel frame can weigh 100g so that could be part of it.
Ti also has the advantage that it does not rust and maybe more dent resistant and no worry about paint chipping. Lastly I read about the ride of Ti, is it really different than steel if the frames have similar stiffness? Thanks for any feedback.