Just to clarefy something about sliders. So to avoid engine braking of purly designed sliders does it mean that I have to drill new holes in to the frame. All that drilling makes me nervous don't they have sliders that are designed to be mounted to the frame but without drilling anything? I need to install sliders to my 919 and to my father-in-law 599 next week. What would be bst to buy? How about these it says that they are frame mounted in the title.