Thanks! We were having a discussion at work, and none of us knew the approximate difference.
I don't remember the costs either, but I was one of those in favor of the subway. Under the previous cost assumptions, I was okay with paying extra to do the subway. If the elevated is 1/5, 1/4 or even 1/3 of the costs, then we need to look at it for sure.
My only concern about the elevated option was the effect on the street vibrancy, but on top of cost there are also some benefits to elevated. Maybe it's just me but as a rider, I always prefer natural light and scenery to nothing but black and perhaps there's a way to tie the DT stations into the +15?