Bolt onLs7 roller tip rocker arm
#3
I personally would worry about the significantly increased rocker arm inertia, it's additional effect on the needed spring pressures and how long the stock single bolt mounting point is able the handle the load, especially if used in DD.
#4
We have used them on several different applications with great results. They do typically require a little modification to the factory pedestal mount for proper clearance, but other than that they are bolt on. We have a few sets on the shelf currently on sale for 979.95.