The Diorama is a 7075 aluminum alloy re-designed Panorama. They gave it the "Boosted" treatment. 7075 aluminum is heavier than 6061, but because of the re-design, the Diorama weighs less than the Panorama. What's interesting is that the profile shape and basic specs are the same.

The redesign is inside - you can't really see it but it's significant. They did, however, change the cup to look different so it's easy to recognize the difference.

Tsukasa specifically requested they do this. He loves the Panorama, but was really curious to see how it would feel Boosted. He finds the Diorama to have a bit more control, but can't decide which one he likes better because they are so different.