The 5k chargers are basically a k31 charger with a t3 exhaust housing in either a .85 or 1.0 a/r. The .85 charger in my opinion would work pretty damn well as a top charger if the bottom is pretty good sized.
egt issues don't seem to be a huge issue with anything less than big injectors.
as far as the drive pressure I havent ever seen how high it is on one but I imagine it would be pretty high. if I were going to run one I would want an external gate on it, but I would want that on any t3 charger.