It looks like you're going to need a pretty sharp bend on the hot pipe to get it past the frame. I'm going to have to say negligible, here.
Judging by the second pic, I'm not seeing any advantage at all. In fact my top mount has similar bends AND a high angle collector as well.
You've got something here. Turbos are heavy. But we're really down to bench race, er, handling here.
OK now you're dreaming. If your shit is getting melted, proper heat managment or materials haven't been used. All of the turbo components are all hot and occupy the same space. Proximity to heat sensitive components is more about design than it's top/bottom mount style.