I have a set of I-factory coils, but have yet to mount them. They are not a direct bolt on modification, and require both to be mounted onto the rhs downtube - according to the instructions (the pics are in english). To do this you are supposed to drill a hole or two into the downtube and install some of those threaded plugs/rivets (can't remember what their correct name is). I haven't done this yet because a) I don't have the correct tool to install said rivets, and b) I'm reluctant to go drilling holes in the downtube.

RS250 coils are a bit bigger and have a different plug attachment to the harness than the standard NSR spade connectors (although I recall reading a thread in the not too distant past that Dan/Gecko Racing managed to find the correct plugs from a UK supplier.