At the 2008 GM Collection event the other day, we had another opportunity to drive the new GMC Yukon Two-Mode Hybrid this time in pretty much finished form. There weren't any surprises and it behaved largely as it did during our first drive last spring. This time though we were able to photograph and shoot some video of the ride as Chris Shunk and John Neff from Autoblog joined me. As before, the hybrid SUVs remain remarkably quiet whether the engine was running or not and transitions between electric-only, four-cylinder and eight-cylinder modes were completely seamless. Shortly after this ride we did find out the official EPA mileage numbers for the GM hybrids would be 21/22 mpg city/highway according to the new 2008 test procedures. Check out the video after the jump.