I am aware of failures but the reason is not because the turbos are remote. It is not location that hurts engines, but setup and tune. STS builds to a price, we used some of their stuff and threw out some of their stuff. Good people but like anything in the aftermarket, you trust blindly at your own peril.
One offs aside, remote mounts are relatively new and are by far the least popular set-up but they are now gaining as perceived shortcomings are found to be false or over-come. If SRT did one, it would not disappoint.
In truth, some cars would best suit a front mount where there is room for full race headers to the front, while others would suit behind the motor for the same reason. The only reason to mount them at the back is because it is not practical to place them under you - as that would be about the ideal spot.... though Mike Moran found a way and ran the worlds first 5 second pass for a turbo car
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Here's a quick remote mount
http://www.youtube.com/watch?v=bYO4K1DqmlY
That held the world record for a while
Here's a fast one - GM was so impressed they allowed them to use their wind tunnel to make it better for next time
http://www.vetteweb.com/tech/vemp_1112_the_worlds_fastest_vette_rock_you_like_a_hurricane/viewall.html