I know that this is the first year where they are giving access to both areas in the Colosseo. Pricing for this exclusive tour online, $126.89 per person. Is it possible to do better than this? Sites I've looked into: victor.com, and walksofitaly.com.

Any advice on this is appreciated, thanks!

There are a number of postings on Fodors concerning the underground colosseum tour. Just search "underground colosseum".
Pierreci.it is the official site for this tour. It is in italian but you can check "English" and it will explain the tours, etc.
The price for the tour (usually a group tour with 20-25 people) is 21.5 Euro (around $31) per person. It is an excellent tour.
You will need to call 39 06 39967700 to book the tour.
Have a great trip.

I second this recommendation.

If you have mobility issues, there is a lift to the second level that gives you an amazing view of the stonework arches as its glass-walled.

bookmarking

lmont, you don't have to top every Rome thread. just use the email icon and email yourself the link.

AJPeabody - not sure what topping is,was just trying to bookmark items to be saved in my "commented" section for help in sorting through vast amounts of information. See the email icon now. Thanks