What exactly needs doing to a DRZ400 shock to get it to fit on the DR650? Drilling and tapping the 650 bottom fork thingy for the DRZ shaft. Drill (and tap?) for the rebound adjuster and grub screw. What spring to use? Stock DR650 is 6.5 kg/mm - Jesse says to use 7.6 kg/mm for my bodyweight/use. Stock DRZ400 is 5.5 kg/mm and RaceTech say to use a 5.7kg/mm for my bodyweight/use. Sounds like the DRZ spring is going to be way too soft. Help!