I fitted electronic ignition to my Mountfield last year. Not a kit like that and not sure if it would fit a Kohler. So I'm not really much help, except to say I was happy with the result. See my post "B&S 11hp April '14".
Got some more bits painted to day. Governor arm, clutch plate and some small brackets. Also drive pulley. That and clutch assembly just fitted tonight.
Had a bit of a change from painting today. The track rod ends on my C-125 were badly worn, so I fitted the ones off the C-121. Today I made some new ones to replace them.
As you can see, they are the worn ones cut down and ends threaded to suit the rose joints. They'll be painted when steering is set.